CA1210847A - Electronic relay of arc detection - Google Patents
Electronic relay of arc detectionInfo
- Publication number
- CA1210847A CA1210847A CA000427977A CA427977A CA1210847A CA 1210847 A CA1210847 A CA 1210847A CA 000427977 A CA000427977 A CA 000427977A CA 427977 A CA427977 A CA 427977A CA 1210847 A CA1210847 A CA 1210847A
- Authority
- CA
- Canada
- Prior art keywords
- circuit
- arc
- voltage
- lag
- tripping
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
- H02H1/0015—Using arc detectors
Abstract
ABSTRACT OF THE DISCLOSURE:
A device for protecting an electrical equipment against a power arc produced along a bus bar system of such an equipment, which comprises an electronic arc detecting relay for sending, in case of arc fault, a tripping order to a tripping coil of a circuit breaker. The electronic relay detects the change in the voltage signal when an arc appears, and elaborates the tripping order in a logic processing cir-cuit, which processing circuit assures distinction between a temporary incident and a real arc fault. This protection device is used in cells and low or medium voltage electric switchboards.
A device for protecting an electrical equipment against a power arc produced along a bus bar system of such an equipment, which comprises an electronic arc detecting relay for sending, in case of arc fault, a tripping order to a tripping coil of a circuit breaker. The electronic relay detects the change in the voltage signal when an arc appears, and elaborates the tripping order in a logic processing cir-cuit, which processing circuit assures distinction between a temporary incident and a real arc fault. This protection device is used in cells and low or medium voltage electric switchboards.
Description
The present invention relates to a device for protecting an electric equipmen~ against a power arc produced along a bar system of the equipment, such a device comprising an arc detecting member for sending, in case of arc fault, a tripping order to a cut off apparatus located above the fault.
The protection against the short-circuits of a Low Voltage switchboard is generally carried out by one or several circuit breakers placed at the switchboard input. These apparatuses are equipped with instantaneous or short delay releases which control the opening of the circuit breaker in reIation- with two conditiorls:
- That a certain current threshold is exceeded, ~ That a certain time-lag is passed in terms of 15 tripping selectivity imperatives between the circuit breaker and other circuit breakers electrically connected in series therewith at lower levels. ~In some cases the time-lag can be zero).
The protection with threshold and possible time-lag is satisfactory for the faults said "straightforward", i.e.
for which the short-circuit current flows only in solid conductors. Then, the bar systems of the switchboard have only to tolerate precisely definite mechanical and thermal stresses. The bar systems can therefore be easily designed to support such stresses.
Unfortunately, this type of fault is rather theoretical and the real short-circuits inside the switchboards are almost always accompanied with an electric arc, even when the fault is initialized by a metal element, the fusion or repulsion of the latter leading very rapidly to the production of an arcO These faults with arc have a double characteristic:
- They are an important source of damages for the equipment and danyer for the staff~ These risks are directly ~.
~2~a~8~
proportional to the time during which the fault is maintained and they are already important for tim~ corresponding to the time lags usually chosen for the shoxt delay releases.
They present a current intensity much lower than a straightforward fault. As a matter of fact, the arc voltage present between conductors represents an important fraction of the net system voltage, thus introducing a limited state which can reach a ratio of 2 to 1. This current decrease is rather favorable as long as the stripping remains assured, but it can have very serious consequences if the so affected cuxrent reaches a value below the tripping threshold of the concerned circuit breaker. Then, the elimination of the Eault will require the tripping of another protection, g~nqrally much slower.
~s a solution to this risk, the inst~ntaneous releases can be set to a threshold as low as possible. However such a solution is limited because transitory peaks of current may cause untimely tripping. Furthermore, setting modifications more or less controlled are always possible under working conditions.
The result of this analysis can be expressed as follows:
- The faults with an arc on the main conductors of the Lcw Voltage switchboards constitute a major risk for the equipment and for the staff.
- This risk is very limited if the fault is cancelled with~ut time-lag by a circuit breaker.
- In case of time-lag the risk increases with the time of this one and can become rather important for the values usually employed (0.2 to 0.5 second).
- Independently of any time-lag notion, the risks become very serious if the fault current intensity is maintained below the tripping threshold of the circuit breaker which ought normally to eliminate it.
~2~
The present invention aims to restore a high level of security for the faults with arc, by introducing, in addition to classical protections, an additional protection through an arc detection relay. The basic principle of this relay is to detect the presence of an arc on the bar system of a switchboard and to send to the circuit breaker an instantaneous tripping order in response to such an arc detection. The above-mentioned risks are thus cleared:
- Any time-lag needs no longer to be introduced insofar as the fault taken into account can only be found immediately below the concerned circuit breakex and as any selectivity notion disappears.
- The criterion of arc detection being not the current, there is no risk of no tripping due to shortage of this current.
It remains to define a measurable criterion reliably revealing the presence of an arc inside the switchboard. Some engineers proposed to use the intense light produced by the arc to excite photosensitive sensors, the change of state of which being used to generate a tripping signal. This technology presents some disadvantages:
- On important switchboards,the necessity to provide several sensors at different positions to eliminate the risk that an arc is not "seen".
- Presence of cabled connectiorsunfavorably influencing the reliability, - Risk to mistake the gleam of a fault arc with the one of the apparatus cut-off.
The criterion proposed by the present invention permits to get rid of these disadvantages. It simply consists in a continuous analysis of the voltage between for example the phases-of a polyphase power circuit. In case of anarc fault on this circuit, this voltage takes a very characteristic aspect, which can be perfectly distinguished from that which is .~,.
. ~TI, ' ' ~2~
usually met, even on a disturbed net system. The function of the arc detection relay is tocarry Ollt this discrimination within a period of time as short as possible and to send the tripping order to the circuit break~r.
First, it can be noticed that the voltage collection may be single-phase, except in a very special arrangPment of the conductors. As a matter of Eact, in most of the cases, these conductors are open mounted bars succeeding side by side at distances of few centimeters. Under these conditions, it is e~ident that an arc arising between two phases will spread very rapidly and consequently such an arc will become detect~ble through the voltage present between any of the three conductors.
More particularly, according to the present inventiQn, there is provided a device for protecting an electric equipment against a power arc produced along a bar system of the equipment, said protecting device comprising an arc detecting member for sending, in case of arc fault, a tripping order to a breaking device located above the ault, wherein the arc detecting member is formed by an electronic relay comprising:
- means for analysingan alternating voltage U present between conductors of the bar system;
- analog means for discriminating the fault, said X5 analOg means being sensitive to change in the waveform of the voltage U and comprising means for generating a control signal when a high temporary derivative of the voltage U
exceeds a predetermined value; and - means for processing the control signal for building up a tripping process following the appearance of an arc fault wherein said analog means comprise a filtering circuit associated with a threshold gate, which is connected to a transformation circuit cooperating with a logic processing circuit playing a role in the elaboration of the tripping .
process by assuring a distinction between a temporary incident and a real arc fault, said processing circuit comprising:
- time-lag members constituted by a first and a second mono-stable trigger circuit both connected to an output of thetransformation circuit, said first and sPcond monostable trigger circuits remaining in the logic state 1 during a first predetermined time-lag and a second predetermined time-lag, respectively, when a first pulse is generated on the output of the transformation circuit, the second time-lag of the second monostable trigger circuit being above the first time-lag of the first monostable trigger circuit;
- a first bistable trigger circuit controlled by the trans~ormation circuit and by the second monostable trigger circuit so that passage of an output of the first bistable trigger circuit to the logic state l happens when the tran~formation circuit emits on its output a second pulse and so that the output of said first bistable txigger circuit is automatically reset to the logic state O
at the end of the second time-lag; and - a second bistable trigger circuit controlled by the transformation circuit and by an output of a logic AND gate receiving an output of the first monostable trigger circuit and the output of the first bistable trigger circuit, the processing circuit comprising means for delivering the tripping order after the emission of three pulses on the output of the transformation circuit including said first and second pulses, the third pulse from the transformation circuit being obligatorily emitted during the second time-lag of the second monostable trigger circuit and after the end of the first time-lag of the first monostable trigger circuit.
~ The experience shows that the so tapped voltage between conductors of the bar system is very clearly distinguished from the voltage under regular service:
- By its form which is very far from a pure sinusoid. In particular wi~h regard to each passage by zero, a very rapid increase is noticed up toa value of about 200 V, giving rise to a derrivative dV/dt much above that which exists under normal operation.
- By its value which is slightly below th~e voltage of the net system.
A5 defined hereinabove~the first criterion used in the arc detection relay is the voltage waveform criterion.
A second criterion of operation used in the arc detection relay may be the value of the voltage U~ For this purpose, the relay may comprise a ~evice detecting the value o~ this alternating voltage U, so as to deliver a lS tripping order when the v~lue of the voltage U is comprised between first and second limits of predetermined values.
The value of the first limit may be chos~n rather low (a few tens of volts for example). Its role is essentially to avoid working ofthe relay when the system is not energized.
The value of the second limit should be above the highest arc voltage which can arise and below the minimum possible voltage of the net system, what lets an adequate margin in the usual equipments.
This detection mode should be associated with a short time-lag during which the voltage value should be held in the above defined zone. This time-lag should be adequate:
- To eliminate voltage fluctuations of very short dura-tion (cut-off by a downstream apparatus, for example).
- To allow the filtering circuit to cancel the harmonics insofar as the basic component is only kept for "U".
An additional criterion of the arc detection relay may be the intensity of the current flowing along the bar system. This criterion may be based on a current threshold low enough so that any arc fault produces a current having an intensity above this threshold, for example in the region of the rated current. Preferably, the relay does not work as long as the current is below the thres]hold.
The three working criterions of the relay using the form and value of the voltage and the current intensity may be associated through a logic AND circuit to avoid the risks of untimely tripping.
Other advanta~es and technical data will more clearly appear from the following non restrictive description of a preferred embodiment of the invention, made for the purpose of exemplification only with reference to the accompanying drawings, in which:
. Figure 1 shows a Low Voltage electrical switch-board equipped with a electronic arc detection relay according to th~ invention;
. Figure 2 represents the synoptic scheme of the electronic arc detection relay;
. Figure 3 shows the scheme of the logic proces-sing circuit of the relay;
. Figure 4 illustrates the diagram of the circuit logic states according to Figure 3;
. Figure 5, which is disposed on the same sheet of formal drawings as Figure 3, represents a development of the invention taking into account the waveform of the voltage, the value of this voltage, as well as the intensity of the current.
Figure 1 schematically shows a cabinet 10 of a Low Voltage distribution switchboard including a bar system 12 provided with conductors Ll, L2 and L3 supplied through an input circuit breaker 14. This circuitbreaker 14, located at the input of the switchboard, is electrically connected to the supply net system or to a transformer Medium Voltage/
Low Voltage. The cabinet 10 can receive any fixed or draw-out electrical apparatus. As an example, a three-phase branch 16 connected to the bar system 12 ,and protected by an output circuit breaker 18 is represented in Figure 1.
The input circuit breaker 14 comprises a magneto-thermal or electronic classical release for carrying out an automatic opening of the contacts of this circuit breaker 14 when the current intensity exceeds a pred~etermined tripping threshold, for example in the case of an Dverload or short-circuit. Auxiliary tripping means can also be incorpoxated inside the circuit breaker 14, in particular for the dettection of a differential fault or of an under-voltage on the net system.
According to the invention, an additionaJ protection is assigned to the input circuit breaker 14, which additional protection comprises an arc detection relay designated by the ge~eral re~erence 20. This relay 20 is used to detect, inside the cabinet ~0, the presence of an arc on the bar system 12 and to send, after processing, an instantaneous tripping order to a coil 22 which controls the opening of the input circuit breaker 14.
A supply circuit AL is associated with the arc detection relay 20 and with the circuit of the tripping coil 22. A first input of the relay 20 is connected through conductors 24 to different phases of the net system above the input circuit hreaker 14. ~ second input of the relay 20 is electriGally connected to current sensors 26 provided to deliver an image of the current flowing along the bar system 12 when the contacts of the circuit breaker 14 are closed. The arc detection is carried out by the relay 20 through continuous analysis of the voltage U, for example, between the conductors 24 connected to two phases of the net syst~m above the circuit breaker 14. This voltage U is identical to the one present between the conductors L1, L2, and L3 of the bar system 12. The occurence of an arc on the bar system 12 is revealed by a change in the waveform of the voltage U, compared with the aspect of this voltage U under normal conditions of operation. The function of the r~lay 20 consists in carrying out this distinction within a period of time as short as possible and in sending a tripping order to the input eircuit breaker 14.
Fig. 2 represents a synoptic scheme of the arc detection relay 20. The main functions of this relay 20 are the following:
- Detection of electric disturbances in the alternating voltage U present between the conductors Ll, L2, and L3 of the bar system 12;
- Distinction of a transitory incident and of an arc fault;
- Storage of the arc fault and tripping of the input circuit breaker 14 above the fault.
The first function consisting in detecting electric disturbances is carried out through an analog part of the relay 20 which comprises a filtering circuit 28 provided with a band-pass active filter associated with a threshold gate 30, sensitive to the amplitude of variation of the ~o voltage U. As a matter of fact, the arc voltage wave is characterized by a rise front having a very high dUt which is detected through derivation of the voltage signal U. The iltering circuit 28 allows only passage of frequencies located within a range in which such sharp rise fronts are located:
- The low cut-off frequency of the band-pass filter is about 300 Hz, so as to reject the fundamental frequency (50 Hz) and its harmonics up to the order of 5.
- The high cut-off frequency is in the neighbourhood of 3~ 8 KHZ so as to suppress the high frequencies having no correlation with an arc fault.
The threshold gate 30 allows to eliminate some interfering phenomena existing under normal operation and to keep exclusively the sharp fronts generating a sudden g ~z~
variation of voltage of a predetermined amplitudeL The threshold gate 30 utilizes a positive threshold and a negative threshold of identical values, so as to take into account the positive and negative variations of the arc voltage. The threshold gate 30 generates an output signal which can present two logic states 0 or 1 indicating, either the presenc~ or the absence of an arc on the bar ~ystem.
Several pulses close in time ~less than 1 ms between two successive pulses) are considered as a single pu~se owing to a diode circuit and a capacitor circuit associated with the output of the threshold gate 30.
The second function which consists in the distinc-tion of a transitory incident and of a real arc fault is carried out by the digital part of the relay 20 following the threshold gate 30. ~s a matter of fact, it should be ensured that the pulse delivered by the threshold gate 30 really corresponds to an arc fault on the bar system 12 and not to transitory incidents originating, for example, from the opening of a circuit breaker located downstream, from a
The protection against the short-circuits of a Low Voltage switchboard is generally carried out by one or several circuit breakers placed at the switchboard input. These apparatuses are equipped with instantaneous or short delay releases which control the opening of the circuit breaker in reIation- with two conditiorls:
- That a certain current threshold is exceeded, ~ That a certain time-lag is passed in terms of 15 tripping selectivity imperatives between the circuit breaker and other circuit breakers electrically connected in series therewith at lower levels. ~In some cases the time-lag can be zero).
The protection with threshold and possible time-lag is satisfactory for the faults said "straightforward", i.e.
for which the short-circuit current flows only in solid conductors. Then, the bar systems of the switchboard have only to tolerate precisely definite mechanical and thermal stresses. The bar systems can therefore be easily designed to support such stresses.
Unfortunately, this type of fault is rather theoretical and the real short-circuits inside the switchboards are almost always accompanied with an electric arc, even when the fault is initialized by a metal element, the fusion or repulsion of the latter leading very rapidly to the production of an arcO These faults with arc have a double characteristic:
- They are an important source of damages for the equipment and danyer for the staff~ These risks are directly ~.
~2~a~8~
proportional to the time during which the fault is maintained and they are already important for tim~ corresponding to the time lags usually chosen for the shoxt delay releases.
They present a current intensity much lower than a straightforward fault. As a matter of fact, the arc voltage present between conductors represents an important fraction of the net system voltage, thus introducing a limited state which can reach a ratio of 2 to 1. This current decrease is rather favorable as long as the stripping remains assured, but it can have very serious consequences if the so affected cuxrent reaches a value below the tripping threshold of the concerned circuit breaker. Then, the elimination of the Eault will require the tripping of another protection, g~nqrally much slower.
~s a solution to this risk, the inst~ntaneous releases can be set to a threshold as low as possible. However such a solution is limited because transitory peaks of current may cause untimely tripping. Furthermore, setting modifications more or less controlled are always possible under working conditions.
The result of this analysis can be expressed as follows:
- The faults with an arc on the main conductors of the Lcw Voltage switchboards constitute a major risk for the equipment and for the staff.
- This risk is very limited if the fault is cancelled with~ut time-lag by a circuit breaker.
- In case of time-lag the risk increases with the time of this one and can become rather important for the values usually employed (0.2 to 0.5 second).
- Independently of any time-lag notion, the risks become very serious if the fault current intensity is maintained below the tripping threshold of the circuit breaker which ought normally to eliminate it.
~2~
The present invention aims to restore a high level of security for the faults with arc, by introducing, in addition to classical protections, an additional protection through an arc detection relay. The basic principle of this relay is to detect the presence of an arc on the bar system of a switchboard and to send to the circuit breaker an instantaneous tripping order in response to such an arc detection. The above-mentioned risks are thus cleared:
- Any time-lag needs no longer to be introduced insofar as the fault taken into account can only be found immediately below the concerned circuit breakex and as any selectivity notion disappears.
- The criterion of arc detection being not the current, there is no risk of no tripping due to shortage of this current.
It remains to define a measurable criterion reliably revealing the presence of an arc inside the switchboard. Some engineers proposed to use the intense light produced by the arc to excite photosensitive sensors, the change of state of which being used to generate a tripping signal. This technology presents some disadvantages:
- On important switchboards,the necessity to provide several sensors at different positions to eliminate the risk that an arc is not "seen".
- Presence of cabled connectiorsunfavorably influencing the reliability, - Risk to mistake the gleam of a fault arc with the one of the apparatus cut-off.
The criterion proposed by the present invention permits to get rid of these disadvantages. It simply consists in a continuous analysis of the voltage between for example the phases-of a polyphase power circuit. In case of anarc fault on this circuit, this voltage takes a very characteristic aspect, which can be perfectly distinguished from that which is .~,.
. ~TI, ' ' ~2~
usually met, even on a disturbed net system. The function of the arc detection relay is tocarry Ollt this discrimination within a period of time as short as possible and to send the tripping order to the circuit break~r.
First, it can be noticed that the voltage collection may be single-phase, except in a very special arrangPment of the conductors. As a matter of Eact, in most of the cases, these conductors are open mounted bars succeeding side by side at distances of few centimeters. Under these conditions, it is e~ident that an arc arising between two phases will spread very rapidly and consequently such an arc will become detect~ble through the voltage present between any of the three conductors.
More particularly, according to the present inventiQn, there is provided a device for protecting an electric equipment against a power arc produced along a bar system of the equipment, said protecting device comprising an arc detecting member for sending, in case of arc fault, a tripping order to a breaking device located above the ault, wherein the arc detecting member is formed by an electronic relay comprising:
- means for analysingan alternating voltage U present between conductors of the bar system;
- analog means for discriminating the fault, said X5 analOg means being sensitive to change in the waveform of the voltage U and comprising means for generating a control signal when a high temporary derivative of the voltage U
exceeds a predetermined value; and - means for processing the control signal for building up a tripping process following the appearance of an arc fault wherein said analog means comprise a filtering circuit associated with a threshold gate, which is connected to a transformation circuit cooperating with a logic processing circuit playing a role in the elaboration of the tripping .
process by assuring a distinction between a temporary incident and a real arc fault, said processing circuit comprising:
- time-lag members constituted by a first and a second mono-stable trigger circuit both connected to an output of thetransformation circuit, said first and sPcond monostable trigger circuits remaining in the logic state 1 during a first predetermined time-lag and a second predetermined time-lag, respectively, when a first pulse is generated on the output of the transformation circuit, the second time-lag of the second monostable trigger circuit being above the first time-lag of the first monostable trigger circuit;
- a first bistable trigger circuit controlled by the trans~ormation circuit and by the second monostable trigger circuit so that passage of an output of the first bistable trigger circuit to the logic state l happens when the tran~formation circuit emits on its output a second pulse and so that the output of said first bistable txigger circuit is automatically reset to the logic state O
at the end of the second time-lag; and - a second bistable trigger circuit controlled by the transformation circuit and by an output of a logic AND gate receiving an output of the first monostable trigger circuit and the output of the first bistable trigger circuit, the processing circuit comprising means for delivering the tripping order after the emission of three pulses on the output of the transformation circuit including said first and second pulses, the third pulse from the transformation circuit being obligatorily emitted during the second time-lag of the second monostable trigger circuit and after the end of the first time-lag of the first monostable trigger circuit.
~ The experience shows that the so tapped voltage between conductors of the bar system is very clearly distinguished from the voltage under regular service:
- By its form which is very far from a pure sinusoid. In particular wi~h regard to each passage by zero, a very rapid increase is noticed up toa value of about 200 V, giving rise to a derrivative dV/dt much above that which exists under normal operation.
- By its value which is slightly below th~e voltage of the net system.
A5 defined hereinabove~the first criterion used in the arc detection relay is the voltage waveform criterion.
A second criterion of operation used in the arc detection relay may be the value of the voltage U~ For this purpose, the relay may comprise a ~evice detecting the value o~ this alternating voltage U, so as to deliver a lS tripping order when the v~lue of the voltage U is comprised between first and second limits of predetermined values.
The value of the first limit may be chos~n rather low (a few tens of volts for example). Its role is essentially to avoid working ofthe relay when the system is not energized.
The value of the second limit should be above the highest arc voltage which can arise and below the minimum possible voltage of the net system, what lets an adequate margin in the usual equipments.
This detection mode should be associated with a short time-lag during which the voltage value should be held in the above defined zone. This time-lag should be adequate:
- To eliminate voltage fluctuations of very short dura-tion (cut-off by a downstream apparatus, for example).
- To allow the filtering circuit to cancel the harmonics insofar as the basic component is only kept for "U".
An additional criterion of the arc detection relay may be the intensity of the current flowing along the bar system. This criterion may be based on a current threshold low enough so that any arc fault produces a current having an intensity above this threshold, for example in the region of the rated current. Preferably, the relay does not work as long as the current is below the thres]hold.
The three working criterions of the relay using the form and value of the voltage and the current intensity may be associated through a logic AND circuit to avoid the risks of untimely tripping.
Other advanta~es and technical data will more clearly appear from the following non restrictive description of a preferred embodiment of the invention, made for the purpose of exemplification only with reference to the accompanying drawings, in which:
. Figure 1 shows a Low Voltage electrical switch-board equipped with a electronic arc detection relay according to th~ invention;
. Figure 2 represents the synoptic scheme of the electronic arc detection relay;
. Figure 3 shows the scheme of the logic proces-sing circuit of the relay;
. Figure 4 illustrates the diagram of the circuit logic states according to Figure 3;
. Figure 5, which is disposed on the same sheet of formal drawings as Figure 3, represents a development of the invention taking into account the waveform of the voltage, the value of this voltage, as well as the intensity of the current.
Figure 1 schematically shows a cabinet 10 of a Low Voltage distribution switchboard including a bar system 12 provided with conductors Ll, L2 and L3 supplied through an input circuit breaker 14. This circuitbreaker 14, located at the input of the switchboard, is electrically connected to the supply net system or to a transformer Medium Voltage/
Low Voltage. The cabinet 10 can receive any fixed or draw-out electrical apparatus. As an example, a three-phase branch 16 connected to the bar system 12 ,and protected by an output circuit breaker 18 is represented in Figure 1.
The input circuit breaker 14 comprises a magneto-thermal or electronic classical release for carrying out an automatic opening of the contacts of this circuit breaker 14 when the current intensity exceeds a pred~etermined tripping threshold, for example in the case of an Dverload or short-circuit. Auxiliary tripping means can also be incorpoxated inside the circuit breaker 14, in particular for the dettection of a differential fault or of an under-voltage on the net system.
According to the invention, an additionaJ protection is assigned to the input circuit breaker 14, which additional protection comprises an arc detection relay designated by the ge~eral re~erence 20. This relay 20 is used to detect, inside the cabinet ~0, the presence of an arc on the bar system 12 and to send, after processing, an instantaneous tripping order to a coil 22 which controls the opening of the input circuit breaker 14.
A supply circuit AL is associated with the arc detection relay 20 and with the circuit of the tripping coil 22. A first input of the relay 20 is connected through conductors 24 to different phases of the net system above the input circuit hreaker 14. ~ second input of the relay 20 is electriGally connected to current sensors 26 provided to deliver an image of the current flowing along the bar system 12 when the contacts of the circuit breaker 14 are closed. The arc detection is carried out by the relay 20 through continuous analysis of the voltage U, for example, between the conductors 24 connected to two phases of the net syst~m above the circuit breaker 14. This voltage U is identical to the one present between the conductors L1, L2, and L3 of the bar system 12. The occurence of an arc on the bar system 12 is revealed by a change in the waveform of the voltage U, compared with the aspect of this voltage U under normal conditions of operation. The function of the r~lay 20 consists in carrying out this distinction within a period of time as short as possible and in sending a tripping order to the input eircuit breaker 14.
Fig. 2 represents a synoptic scheme of the arc detection relay 20. The main functions of this relay 20 are the following:
- Detection of electric disturbances in the alternating voltage U present between the conductors Ll, L2, and L3 of the bar system 12;
- Distinction of a transitory incident and of an arc fault;
- Storage of the arc fault and tripping of the input circuit breaker 14 above the fault.
The first function consisting in detecting electric disturbances is carried out through an analog part of the relay 20 which comprises a filtering circuit 28 provided with a band-pass active filter associated with a threshold gate 30, sensitive to the amplitude of variation of the ~o voltage U. As a matter of fact, the arc voltage wave is characterized by a rise front having a very high dUt which is detected through derivation of the voltage signal U. The iltering circuit 28 allows only passage of frequencies located within a range in which such sharp rise fronts are located:
- The low cut-off frequency of the band-pass filter is about 300 Hz, so as to reject the fundamental frequency (50 Hz) and its harmonics up to the order of 5.
- The high cut-off frequency is in the neighbourhood of 3~ 8 KHZ so as to suppress the high frequencies having no correlation with an arc fault.
The threshold gate 30 allows to eliminate some interfering phenomena existing under normal operation and to keep exclusively the sharp fronts generating a sudden g ~z~
variation of voltage of a predetermined amplitudeL The threshold gate 30 utilizes a positive threshold and a negative threshold of identical values, so as to take into account the positive and negative variations of the arc voltage. The threshold gate 30 generates an output signal which can present two logic states 0 or 1 indicating, either the presenc~ or the absence of an arc on the bar ~ystem.
Several pulses close in time ~less than 1 ms between two successive pulses) are considered as a single pu~se owing to a diode circuit and a capacitor circuit associated with the output of the threshold gate 30.
The second function which consists in the distinc-tion of a transitory incident and of a real arc fault is carried out by the digital part of the relay 20 following the threshold gate 30. ~s a matter of fact, it should be ensured that the pulse delivered by the threshold gate 30 really corresponds to an arc fault on the bar system 12 and not to transitory incidents originating, for example, from the opening of a circuit breaker located downstream, from a
2~ transitory absence of voltage, from the phenomena of recovery transitory voltage giving rise to voltage oscillations or to the supply of the Low Voltage net system by switching-on a circuit breaker, the contacts of which bounce. The output of the threshold gate 30 is connected to a transformation circuit 32 connected to a logic processing circuit 34 which will be described in detail hereinafter with refererlce to Fig. 3 of the drawings.
The logic processing circuit 34 (Fig. 3) provided with sequential binary operators comprises, as an example, two monostable trigger circuits 36, 38 and two bistable RS
trigger circuits 40, 42 energized by the supply circuit AL.
The inputs of the trigger circuits 36, 38, 40 are connected to the output o the transformation circuit 32, and the out-put of the second bistable trigger circuit 42 delivers a logic .
~ ~, ~2~
level 1 or 0 indicating the presence or the absence of an arc fault. One of the inputs of the triqger circuit 42 is connected to the transformation circuit 12 through a logic gate 44. The other input of the trigger circuit 42 is connected to the output of a logic AND gate 46, the inputs of which are respectively connected to the outputs of the trigger circuits 36 and 40. A reset circuit RAZ provided with a manually operated switch 48 is associated with the bistable trigger circuit 42.
The operation of the logic processing circuit 34, according to Fig. 3, is illustrated on the diagram of Fig.4:
- The first pulse generated by the circuit 32 at time tl produces tripping of the two monostable trigger circuits 36 and 38. The outputs of these two trigger circuits 36 and 38 remain in logic state 1 during predetermined time-lags T1 and T2, the time-lag T2 of the second monostable triggex circuit 38 being above the time lag Tl of the first monostable trigger circuit 36.
- The first bistable trigger circuit 40 generates a second pulse at time t2 during the time-lag T1 by producing on its output a transition logic state O - logic state 1.
This bistable trigger circuit 40 is automatically reset at the end of the time-lag T2 of the second monostable trigyer circuit 38O The logic state 1 of the first bistable trigger circuit 40 indicates the emission of two pulses by the trans-formation circuit 32.
A hole or transitory absence of voltage can also generate two pulses with sharp fronts, one when the voltage disappears and another when it comes back. To avoid an untimely working of the arc detection relay 20, the logic processing circuit 34 i8 designed to generate a tripping order only after a counting of three pulses.
The third pulse from the circuit 32 to be taken nto consideration arld which produces tripping of the relay ~;
20, should arise for example, at time t3 after the end of the time-lag Tl gener2ted by the first monostable trigger circuit 36 and obligatorily during the time-lag T2 generated by the second monostable trigger circuit 38. The first bist-able trigger circuit 40 is then in state 1 and the logic ANDgate 46 is released. The fault is thus stored by the second bistable trigger circuit 42 which produces on its out-put a logic state 0 logic state 1 transition.
The third function consisting in StOring the arc fault and tripping the input circuit breaker 14 is actuated by the output trigger circuit 42 of the logic processing circuit 34. The change from the logic state 0 to the logic state 1 of the second bistable trigger circuit 42 generates a tripping pulse applied to a pulse generator 50 connected lS to the release trigger electrode of a static switch 52, in particular a triac, disposed in series with the tripping coil 22. Conduction of the triac 52 produce activatiOn of the coil 22 followed by the opening of the contacts of the input circuit breaker 14. The presence of the arc fault is simultaneously indicated at a remote location by means of a visualization member 54 connected tO the trigger circuit 42 of the circuit 34 through a control device 56.
Th~ detection of the arc fault by the circuit of Fig. 2 is based on the chage in the form of the wave of the arc voltage, owing to the continuous analysis of the voltage U between the power conductors, thus constituting a first working criterion of the relay 20. The logic circuit 34 should count three pulses before activating the tripping.
It was noticed that the presence of an arc inside the switchboard gives rise to a voltage having a fun~ntal com~onent which is slightly below the normal voltage of the net systemO
It is then easy to use it as another wor3cing criterion of the relay 20, by designing this relay so that a tripping order is sent if the tapped effective voltage "U" is comprised between two limits "U1" and "U2".
The value "Ul t- should be chosen low enough (a few tens of volts, for example). Its function is essentially to prevent working of the relay 20 when the system is not energi~ed.
The value "U2" should be above the highest arc voltage which can be produced and below the minimum possible voltage sf the net system. This leaves a sufficient margin in the usual equipments.
This detection mode can be associated with a time-lag during which the voltage can be maintained in the required ~ead zone. This time-lag should be adeguate to eliminate fluctuations of very short duration voltage (cut-o~ by a downstream apparatus for example). This second lS criterion is built up in a detecting device 60 (Fig. 5~.
To improve the reliability of the system, the two criterions of ~he relay 20 based on the waveform and the effective value of the voltage "U" are associated by means of a logic AND gate 62 (Fig. 5). The two criterions should be simultaneously met so as to permit delivering of the tripping order to the tripping coil 22 of the relay 20.
The risks of untimely tripping are thus greatly reduced. Indeed, if a probability P1 is assumed for ab-normal appearance of the waveform cxiterion and P2 for abnormal appearance of the voltage value criterion, the probability for an untimely tripping of the relay is reduced to Pl x P2.
This reliability can still be improved by adding a third criterion, in the circumstances the current. This criterion is based on a threshold Is low enough 50 that the arc current is obligatorily above this threshold. The current criterion is built up in a comparing element 64 (Fig. 5) having an input connected to the current sensors 26 and an output connected to the third input of the logic AND gate 62.
The action of the comparing element 64 occurs only when the ~Z~8fl~7 current I flowing through the bar system 12 is above the threshold Is.
According to Fig. 5, three conditions must be met to obtain delivering by the logic gate 62 of a -tripping order to the triac 52:
- Counting of three pulses by the logic processing curcuit 34, the third pulse occurring obligatorily during the time-lag T2;
- Release of the circuit 60 when the effective value of the voltage "U" is comprised between the lirnits "Ul" and "U2~;
- Release of the compaxing element 64 when the current I is above the threshold Is.
In a first embodiment, the arc de~ection relay 20 according to Figs. 1 to 5 can be presented as an independant lS component which can be set up inside the switchboard to be protected and connected in a classical manner, on the one hand to the bar system 12 and, on the other hand, to the circuit breaker 14 to be actuated(and moreover if necessary, to the auxiliary source if such a source is provided, and to a current sensor 26, if the current criterion is used).
Consequently, this embodiment assumes wired con-nections which should be minimized by positioning the relay 20 as close as possible to the circuit breaker 14, while taking care that the same is not e~posed to a possible arc.
Such a type of relay is necessary to equip an already existing equipment.
In a second embodiment, the relay 20 is incorporated inside the circuit breaker 14 itself. This presents many advantages : first, the wired connections are suppressed.
Then, if the circuit breaker is already equipped with a static release, a certain number of functions are alxeady present therein and the arc detection relay 20 is not presented anymore as additional components in limited amount.
This last type of embodiment permits, in particular, .
~Z~ 7 to take into consideration the current criterion very easily, this information being always present on a level with the release of the circuit breaker 14.
It can be found parts of equipments which are not S protected by a circuit breaker. It is the case, for example, of bars which are immediately below an alt:ernator. Then an arc detection relay can still be used, but: the order given by the latter will be used to de-activate the alternator.
The supply circuit AL is combined with the relay 20 and comprises a component capable of storing electric energy, in particular a capacitor or an accumulator. The tripping coil 22 should be supplied under an appropriate voltage and with an adequate energy. Two cases should be distinguished:
lS - An independant auxiliary source is available. The function of the relay is then confined to connect this source with the coil circuit.
- The coil 22 can be supplied only by the net system voltage.
At the time of the fault, this one is turned into an arc voltage, the form and value of which can largely fluctuate.
Then it should be ensured that this voltage will be always adequae to actuate the coil, even in minimal value, which means that it will be very superabundant in maximum value.
Consequently, the coil should be designed to tolerate this maximum voltage value only during a very short period of time, suf~icient enough to ensure the tripping.
The present invention is not at all limited to the embodiments more fully described hereinabove and/or shown in the accompanying drawings, but on the contrary it extends to any variant remaining in the limit of the electrical engineer-ing and electronic equivalences, especially those in which the arc detection relay would be used inside metal-clad substations provided with metal housings or high or medium voltage distribution panels.
The logic processing circuit 34 (Fig. 3) provided with sequential binary operators comprises, as an example, two monostable trigger circuits 36, 38 and two bistable RS
trigger circuits 40, 42 energized by the supply circuit AL.
The inputs of the trigger circuits 36, 38, 40 are connected to the output o the transformation circuit 32, and the out-put of the second bistable trigger circuit 42 delivers a logic .
~ ~, ~2~
level 1 or 0 indicating the presence or the absence of an arc fault. One of the inputs of the triqger circuit 42 is connected to the transformation circuit 12 through a logic gate 44. The other input of the trigger circuit 42 is connected to the output of a logic AND gate 46, the inputs of which are respectively connected to the outputs of the trigger circuits 36 and 40. A reset circuit RAZ provided with a manually operated switch 48 is associated with the bistable trigger circuit 42.
The operation of the logic processing circuit 34, according to Fig. 3, is illustrated on the diagram of Fig.4:
- The first pulse generated by the circuit 32 at time tl produces tripping of the two monostable trigger circuits 36 and 38. The outputs of these two trigger circuits 36 and 38 remain in logic state 1 during predetermined time-lags T1 and T2, the time-lag T2 of the second monostable triggex circuit 38 being above the time lag Tl of the first monostable trigger circuit 36.
- The first bistable trigger circuit 40 generates a second pulse at time t2 during the time-lag T1 by producing on its output a transition logic state O - logic state 1.
This bistable trigger circuit 40 is automatically reset at the end of the time-lag T2 of the second monostable trigyer circuit 38O The logic state 1 of the first bistable trigger circuit 40 indicates the emission of two pulses by the trans-formation circuit 32.
A hole or transitory absence of voltage can also generate two pulses with sharp fronts, one when the voltage disappears and another when it comes back. To avoid an untimely working of the arc detection relay 20, the logic processing circuit 34 i8 designed to generate a tripping order only after a counting of three pulses.
The third pulse from the circuit 32 to be taken nto consideration arld which produces tripping of the relay ~;
20, should arise for example, at time t3 after the end of the time-lag Tl gener2ted by the first monostable trigger circuit 36 and obligatorily during the time-lag T2 generated by the second monostable trigger circuit 38. The first bist-able trigger circuit 40 is then in state 1 and the logic ANDgate 46 is released. The fault is thus stored by the second bistable trigger circuit 42 which produces on its out-put a logic state 0 logic state 1 transition.
The third function consisting in StOring the arc fault and tripping the input circuit breaker 14 is actuated by the output trigger circuit 42 of the logic processing circuit 34. The change from the logic state 0 to the logic state 1 of the second bistable trigger circuit 42 generates a tripping pulse applied to a pulse generator 50 connected lS to the release trigger electrode of a static switch 52, in particular a triac, disposed in series with the tripping coil 22. Conduction of the triac 52 produce activatiOn of the coil 22 followed by the opening of the contacts of the input circuit breaker 14. The presence of the arc fault is simultaneously indicated at a remote location by means of a visualization member 54 connected tO the trigger circuit 42 of the circuit 34 through a control device 56.
Th~ detection of the arc fault by the circuit of Fig. 2 is based on the chage in the form of the wave of the arc voltage, owing to the continuous analysis of the voltage U between the power conductors, thus constituting a first working criterion of the relay 20. The logic circuit 34 should count three pulses before activating the tripping.
It was noticed that the presence of an arc inside the switchboard gives rise to a voltage having a fun~ntal com~onent which is slightly below the normal voltage of the net systemO
It is then easy to use it as another wor3cing criterion of the relay 20, by designing this relay so that a tripping order is sent if the tapped effective voltage "U" is comprised between two limits "U1" and "U2".
The value "Ul t- should be chosen low enough (a few tens of volts, for example). Its function is essentially to prevent working of the relay 20 when the system is not energi~ed.
The value "U2" should be above the highest arc voltage which can be produced and below the minimum possible voltage sf the net system. This leaves a sufficient margin in the usual equipments.
This detection mode can be associated with a time-lag during which the voltage can be maintained in the required ~ead zone. This time-lag should be adeguate to eliminate fluctuations of very short duration voltage (cut-o~ by a downstream apparatus for example). This second lS criterion is built up in a detecting device 60 (Fig. 5~.
To improve the reliability of the system, the two criterions of ~he relay 20 based on the waveform and the effective value of the voltage "U" are associated by means of a logic AND gate 62 (Fig. 5). The two criterions should be simultaneously met so as to permit delivering of the tripping order to the tripping coil 22 of the relay 20.
The risks of untimely tripping are thus greatly reduced. Indeed, if a probability P1 is assumed for ab-normal appearance of the waveform cxiterion and P2 for abnormal appearance of the voltage value criterion, the probability for an untimely tripping of the relay is reduced to Pl x P2.
This reliability can still be improved by adding a third criterion, in the circumstances the current. This criterion is based on a threshold Is low enough 50 that the arc current is obligatorily above this threshold. The current criterion is built up in a comparing element 64 (Fig. 5) having an input connected to the current sensors 26 and an output connected to the third input of the logic AND gate 62.
The action of the comparing element 64 occurs only when the ~Z~8fl~7 current I flowing through the bar system 12 is above the threshold Is.
According to Fig. 5, three conditions must be met to obtain delivering by the logic gate 62 of a -tripping order to the triac 52:
- Counting of three pulses by the logic processing curcuit 34, the third pulse occurring obligatorily during the time-lag T2;
- Release of the circuit 60 when the effective value of the voltage "U" is comprised between the lirnits "Ul" and "U2~;
- Release of the compaxing element 64 when the current I is above the threshold Is.
In a first embodiment, the arc de~ection relay 20 according to Figs. 1 to 5 can be presented as an independant lS component which can be set up inside the switchboard to be protected and connected in a classical manner, on the one hand to the bar system 12 and, on the other hand, to the circuit breaker 14 to be actuated(and moreover if necessary, to the auxiliary source if such a source is provided, and to a current sensor 26, if the current criterion is used).
Consequently, this embodiment assumes wired con-nections which should be minimized by positioning the relay 20 as close as possible to the circuit breaker 14, while taking care that the same is not e~posed to a possible arc.
Such a type of relay is necessary to equip an already existing equipment.
In a second embodiment, the relay 20 is incorporated inside the circuit breaker 14 itself. This presents many advantages : first, the wired connections are suppressed.
Then, if the circuit breaker is already equipped with a static release, a certain number of functions are alxeady present therein and the arc detection relay 20 is not presented anymore as additional components in limited amount.
This last type of embodiment permits, in particular, .
~Z~ 7 to take into consideration the current criterion very easily, this information being always present on a level with the release of the circuit breaker 14.
It can be found parts of equipments which are not S protected by a circuit breaker. It is the case, for example, of bars which are immediately below an alt:ernator. Then an arc detection relay can still be used, but: the order given by the latter will be used to de-activate the alternator.
The supply circuit AL is combined with the relay 20 and comprises a component capable of storing electric energy, in particular a capacitor or an accumulator. The tripping coil 22 should be supplied under an appropriate voltage and with an adequate energy. Two cases should be distinguished:
lS - An independant auxiliary source is available. The function of the relay is then confined to connect this source with the coil circuit.
- The coil 22 can be supplied only by the net system voltage.
At the time of the fault, this one is turned into an arc voltage, the form and value of which can largely fluctuate.
Then it should be ensured that this voltage will be always adequae to actuate the coil, even in minimal value, which means that it will be very superabundant in maximum value.
Consequently, the coil should be designed to tolerate this maximum voltage value only during a very short period of time, suf~icient enough to ensure the tripping.
The present invention is not at all limited to the embodiments more fully described hereinabove and/or shown in the accompanying drawings, but on the contrary it extends to any variant remaining in the limit of the electrical engineer-ing and electronic equivalences, especially those in which the arc detection relay would be used inside metal-clad substations provided with metal housings or high or medium voltage distribution panels.
Claims (5)
1. Device for protecting an electric equipment against a power arc produced along a bar system of the equipment, said protecting device comprising an arc detect-ing member for sending, in case of arc fault, a tripping order to a breaking device located above the fault, wherein the arc detecting member is formed by an electronic relay comprising:
- means for analysing an alternating voltage U present between conductors of the bar system;
- analog means for discriminating the fault, said analog means being sensitive to change in the waveform of the voltage U and comprising means for generating a control signal when a high temporary derivative of the voltage U exceeds a pre-determined value; and - means for processing the control signal for building up a tripping process following the appearance of an arc fault;
wherein said analog means comprise a filtering circuit associated with a threshold gate, which is connected to a transformation circuit cooperating with a logic processing circuit playing a role in the elaboration of the trip-ping process by assuring a distinction between a temporary incident and a real arc fault, said processing circuit comprising:
- time-lag members constituted by a first and a second mono-stable trigger circuit both connected to an output of the transformation circuit,said first and second monostable trigger circuits remaining in the logic state 1 during a first predetermined time-lag and a second predetermined time-lag, respectively, when a first pulse is generated on the output of the transformation circuit, the second time-lag of the second monostable trigger circuit being above the first time-lag of the first monostable trigger circuit;
- a first bistable trigger circuit controlled by the transformation circuit and by the second monostable trigger circuit so that passage of an output of the first bistable trigger circuit to the logic state 1 happens when the trans-formation circuit emits on its output a second pulse and so that the output of said first bistable trigger circuit is automatically reset to the logic state 0 at the end of the second time-lag; and - a second bistable trigger circuit controlled by the transformation circuit and by an output of a logic AND gate receiving an output of the first monostable trigger circuit and the output of the first bistable trigger circuit, the processing circuit comprising means for delivering the trip-ping order after the emission of three pulses on the output of the transformation circuit including said first and second pulses, the third pulse from the transformation circuit being obligatorily emitted during the second time-lag of the second monostable trigger circuit and after the end of the first time-lag of the first monostable trigger circuit.
- means for analysing an alternating voltage U present between conductors of the bar system;
- analog means for discriminating the fault, said analog means being sensitive to change in the waveform of the voltage U and comprising means for generating a control signal when a high temporary derivative of the voltage U exceeds a pre-determined value; and - means for processing the control signal for building up a tripping process following the appearance of an arc fault;
wherein said analog means comprise a filtering circuit associated with a threshold gate, which is connected to a transformation circuit cooperating with a logic processing circuit playing a role in the elaboration of the trip-ping process by assuring a distinction between a temporary incident and a real arc fault, said processing circuit comprising:
- time-lag members constituted by a first and a second mono-stable trigger circuit both connected to an output of the transformation circuit,said first and second monostable trigger circuits remaining in the logic state 1 during a first predetermined time-lag and a second predetermined time-lag, respectively, when a first pulse is generated on the output of the transformation circuit, the second time-lag of the second monostable trigger circuit being above the first time-lag of the first monostable trigger circuit;
- a first bistable trigger circuit controlled by the transformation circuit and by the second monostable trigger circuit so that passage of an output of the first bistable trigger circuit to the logic state 1 happens when the trans-formation circuit emits on its output a second pulse and so that the output of said first bistable trigger circuit is automatically reset to the logic state 0 at the end of the second time-lag; and - a second bistable trigger circuit controlled by the transformation circuit and by an output of a logic AND gate receiving an output of the first monostable trigger circuit and the output of the first bistable trigger circuit, the processing circuit comprising means for delivering the trip-ping order after the emission of three pulses on the output of the transformation circuit including said first and second pulses, the third pulse from the transformation circuit being obligatorily emitted during the second time-lag of the second monostable trigger circuit and after the end of the first time-lag of the first monostable trigger circuit.
2. Protecting device according to claim 1, wherein said electronic relay comprises a device for detecting the value of the voltage U, and for generating a tripping order when the voltage U is comprised between two limits of prede-termined values.
3. Protecting device according to claim 2, wherein said detecting and generating device and the logic processing circuit are connected to a logic AND circuit actuating a static switch controlling the excitation of a tripping coil of the breaking device located above the fault.
4. Protecting device according to claim 3, wherein the electronic relay further comprises a current comparing element generating an order to said logic AND circuit, when the current flowing along the bar system is above a prede-termined curent threshold.
5. Protecting device according to claim 4, wherein the tripping coil is supplied by the fault voltage, when the tripping occurs.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8208926 | 1982-05-19 | ||
| FR8208926A FR2527381A1 (en) | 1982-05-19 | 1982-05-19 | ELECTRONIC ARC DETECTION RELAY |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1210847A true CA1210847A (en) | 1986-09-02 |
Family
ID=9274251
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000427977A Expired CA1210847A (en) | 1982-05-19 | 1983-05-12 | Electronic relay of arc detection |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0094871B1 (en) |
| AU (1) | AU555322B2 (en) |
| CA (1) | CA1210847A (en) |
| DE (1) | DE3361547D1 (en) |
| ES (1) | ES8402980A1 (en) |
| FR (1) | FR2527381A1 (en) |
| ZA (1) | ZA833351B (en) |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4835648A (en) * | 1985-03-26 | 1989-05-30 | Mitsubishi Denki Kabushiki Kaisha | Gas insulated switchgear |
| US5452223A (en) * | 1993-08-20 | 1995-09-19 | Eaton Corporation | Arc detection using current variation |
| US5691869A (en) * | 1995-06-06 | 1997-11-25 | Eaton Corporation | Low cost apparatus for detecting arcing faults and circuit breaker incorporating same |
| US5726577A (en) * | 1996-04-17 | 1998-03-10 | Eaton Corporation | Apparatus for detecting and responding to series arcs in AC electrical systems |
| US5818237A (en) * | 1996-06-10 | 1998-10-06 | Eaton Corporation | Apparatus for envelope detection of low current arcs |
| US5940256A (en) * | 1993-02-26 | 1999-08-17 | Eaton Corporation | Circuit breaker responsive to repeated in-rush currents produced by a sputtering arc fault |
| WO2017207032A1 (en) * | 2016-05-31 | 2017-12-07 | Siemens Aktiengesellschaft | Arcing fault recognition unit |
| US11088527B2 (en) | 2016-05-31 | 2021-08-10 | Siemens Aktiengesellschaft | Arc fault identification unit |
| US11088526B2 (en) | 2016-05-31 | 2021-08-10 | Siemens Aktiengesellschaft | Arcing fault recognition unit |
| US11205891B2 (en) | 2016-05-31 | 2021-12-21 | Siemens Aktiengesellschaft | Arc fault detection unit |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5185685A (en) * | 1991-03-28 | 1993-02-09 | Eaton Corporation | Field sensing arc detection |
| US6532424B1 (en) | 1995-03-13 | 2003-03-11 | Square D Company | Electrical fault detection circuit with dual-mode power supply |
| US6242993B1 (en) | 1995-03-13 | 2001-06-05 | Square D Company | Apparatus for use in arcing fault detection systems |
| US6377427B1 (en) | 1995-03-13 | 2002-04-23 | Square D Company | Arc fault protected electrical receptacle |
| US5825598A (en) * | 1997-02-11 | 1998-10-20 | Square D Company | Arcing fault detection system installed in a panelboard |
| US6452767B1 (en) | 1995-03-13 | 2002-09-17 | Square D Company | Arcing fault detection system for a secondary line of a current transformer |
| US5847913A (en) | 1997-02-21 | 1998-12-08 | Square D Company | Trip indicators for circuit protection devices |
| US6625550B1 (en) | 1998-02-19 | 2003-09-23 | Square D Company | Arc fault detection for aircraft |
| US6782329B2 (en) | 1998-02-19 | 2004-08-24 | Square D Company | Detection of arcing faults using bifurcated wiring system |
| US6567250B1 (en) | 1998-02-19 | 2003-05-20 | Square D Company | Arc fault protected device |
| US6477021B1 (en) | 1998-02-19 | 2002-11-05 | Square D Company | Blocking/inhibiting operation in an arc fault detection system |
| US6621669B1 (en) | 1998-02-19 | 2003-09-16 | Square D Company | Arc fault receptacle with a feed-through connection |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR799271A (en) * | 1935-12-13 | 1936-06-10 | Apparatus intended to detect the presence of abnormal irregularities in an electric current | |
| CH369815A (en) * | 1957-09-26 | 1963-06-15 | Siemens Ag | Arrangement to avoid impermissibly high short-circuit arc energy in electrical systems |
| DE1126011B (en) * | 1961-02-03 | 1962-03-22 | Siemens Ag | Device for detecting and locating arcing faults in electrical systems |
| US3588611A (en) * | 1969-10-31 | 1971-06-28 | Westinghouse Electric Corp | Transmission line arc detection and location system |
| DE2103472A1 (en) * | 1971-01-18 | 1972-08-03 | Siemens Ag | Circuit arrangement for the detection of electrical alternating current arcs, |
| EP0053229B1 (en) * | 1980-12-01 | 1985-04-10 | VEB Starkstrom-Anlagenbau Leipzig-Halle | Method and circuit for detecting and breaking disturbing electric arcs |
-
1982
- 1982-05-19 FR FR8208926A patent/FR2527381A1/en active Granted
-
1983
- 1983-05-09 EP EP83400934A patent/EP0094871B1/en not_active Expired
- 1983-05-09 DE DE8383400934T patent/DE3361547D1/en not_active Expired
- 1983-05-10 ZA ZA833351A patent/ZA833351B/en unknown
- 1983-05-12 CA CA000427977A patent/CA1210847A/en not_active Expired
- 1983-05-14 ES ES522405A patent/ES8402980A1/en not_active Expired
- 1983-05-19 AU AU14859/83A patent/AU555322B2/en not_active Ceased
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4835648A (en) * | 1985-03-26 | 1989-05-30 | Mitsubishi Denki Kabushiki Kaisha | Gas insulated switchgear |
| US5940256A (en) * | 1993-02-26 | 1999-08-17 | Eaton Corporation | Circuit breaker responsive to repeated in-rush currents produced by a sputtering arc fault |
| US6057997A (en) * | 1993-02-26 | 2000-05-02 | Eaton Corporation | Circuit breaker responsive to repeated in-rush currents produced by a sputtering arc fault |
| US5452223A (en) * | 1993-08-20 | 1995-09-19 | Eaton Corporation | Arc detection using current variation |
| US5561605A (en) * | 1993-08-20 | 1996-10-01 | Eaton Corporation | Arc detection using current variation |
| US5691869A (en) * | 1995-06-06 | 1997-11-25 | Eaton Corporation | Low cost apparatus for detecting arcing faults and circuit breaker incorporating same |
| US5726577A (en) * | 1996-04-17 | 1998-03-10 | Eaton Corporation | Apparatus for detecting and responding to series arcs in AC electrical systems |
| US5818237A (en) * | 1996-06-10 | 1998-10-06 | Eaton Corporation | Apparatus for envelope detection of low current arcs |
| WO2017207032A1 (en) * | 2016-05-31 | 2017-12-07 | Siemens Aktiengesellschaft | Arcing fault recognition unit |
| CN109478774A (en) * | 2016-05-31 | 2019-03-15 | 西门子股份公司 | Fault electric arc recognition unit |
| US11088527B2 (en) | 2016-05-31 | 2021-08-10 | Siemens Aktiengesellschaft | Arc fault identification unit |
| US11088526B2 (en) | 2016-05-31 | 2021-08-10 | Siemens Aktiengesellschaft | Arcing fault recognition unit |
| US11205891B2 (en) | 2016-05-31 | 2021-12-21 | Siemens Aktiengesellschaft | Arc fault detection unit |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2527381A1 (en) | 1983-11-25 |
| EP0094871A1 (en) | 1983-11-23 |
| DE3361547D1 (en) | 1986-01-30 |
| EP0094871B1 (en) | 1985-12-18 |
| FR2527381B1 (en) | 1985-04-12 |
| ES522405A0 (en) | 1984-03-01 |
| ZA833351B (en) | 1984-02-29 |
| AU555322B2 (en) | 1986-09-18 |
| ES8402980A1 (en) | 1984-03-01 |
| AU1485983A (en) | 1983-11-24 |
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