CA1158711A - Alarm and control system for high voltage capacitor bank - Google Patents
Alarm and control system for high voltage capacitor bankInfo
- Publication number
- CA1158711A CA1158711A CA000370912A CA370912A CA1158711A CA 1158711 A CA1158711 A CA 1158711A CA 000370912 A CA000370912 A CA 000370912A CA 370912 A CA370912 A CA 370912A CA 1158711 A CA1158711 A CA 1158711A
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- CA
- Canada
- Prior art keywords
- capacitor
- capacitor bank
- electrical signals
- alarm
- light
- Prior art date
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Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/16—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for capacitors
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Protection Of Static Devices (AREA)
- Emergency Alarm Devices (AREA)
Abstract
Case 2512 ALARM AND CONTROL SYSTEM FOR HIGH VOLTAGES
CAPACITOR BANK
ABSTRACT OF THE DISCLOSURE
The present invention relates to an alarm and control system for a capacitor bank which is connected in shunt circuit relation with a highvvoltage direct current power supply. The capacitor bank comprises a plurality of serially connected groups of capacitors where each capacitor of a group is connected in parallel circuit relation. The alarm and control system comprises a plurality of branch circuits each including a grading resistor and a light source emits are connected in series. The light source emits light in response to an electrical current passing through the source. Each of the branch circuits is connected in shunt circuit relation with a respective one of the capacitor group such that the occurrence of a short circuit or low impedance in one of the capacitors of the group causes electrical current flow to bypass the respective branch circuit which result in no light being emitted from the light source. The system includes optical to electrical converter for converting light emitted from the light sources into corresponding electrical signals and includes a control circuit which in response to the presence of all but a predetermined number of electrical signals generates an alarm signal and a control signal. The power supply in response to the generation of a control signal may discontinue power transmission.
CAPACITOR BANK
ABSTRACT OF THE DISCLOSURE
The present invention relates to an alarm and control system for a capacitor bank which is connected in shunt circuit relation with a highvvoltage direct current power supply. The capacitor bank comprises a plurality of serially connected groups of capacitors where each capacitor of a group is connected in parallel circuit relation. The alarm and control system comprises a plurality of branch circuits each including a grading resistor and a light source emits are connected in series. The light source emits light in response to an electrical current passing through the source. Each of the branch circuits is connected in shunt circuit relation with a respective one of the capacitor group such that the occurrence of a short circuit or low impedance in one of the capacitors of the group causes electrical current flow to bypass the respective branch circuit which result in no light being emitted from the light source. The system includes optical to electrical converter for converting light emitted from the light sources into corresponding electrical signals and includes a control circuit which in response to the presence of all but a predetermined number of electrical signals generates an alarm signal and a control signal. The power supply in response to the generation of a control signal may discontinue power transmission.
Description
- 1 - Case 2512 ALARM AND CONTROL SYSTEM FOR HIGH YOLTAGE
CAPACITOR BANK
The present invention relates to an alarm and control system for a capacitor bank. In partieular, it relates to alarm and control system for shunt eapaeitor banks connected across high voltage terminals of an electric power system.
Capaeitor banks suitable for use in hlgh voltage transmission commonly comprise a plurallty o parallel connected capacitors which form capacitor groups that are connected in series. The capaci-tor banks provide power factor correction for alternating current transmission and distribution cireuits. Also, the eapaeitor banks function as high voltage harmonic filters for power rectifiers and invertors of high voltage direct eurrent power transmission systems.
In the event that one or more capacitors of the capaeitor bank fail, it is imperative that such failures be detected; otherwise, the excess voltage made available by the failure of the capacitors may lead to the destruetion of a good number of the remaining funetioning capacitors in the capacitor bank.
Conventional means for detecting the failure of capaeitors in a capacitor bank, particularly when such eapacitor banks are utilized as high voltage direet current filters, comprise current differential, voltage differential and change in impedanee systems.
Case 2512 The detection of failed capacitors in a capacitor bank employed as a high vol-tage d~ filter, however, is complicated by the fact that the alternating harmonic current flow ~hrough the filter is relatively small and caries under no fault conditions as a function of such variables as ambient temperature, convertor firing angle and convertor current loading. These conventional detection means have difficulty in distinguishing between failed capacitors or variations in one or more o a combination of the above mentioned complications.
Another system for detecting the failure of a capacitor in a capacitor ban~ is disclosed in U.S.
Patent No. 3,973,169 which issued August 3, 1976, to Charles H. Titus. This system discloses an over voltage detector which is connected across each section of parallel capacitors in a capacitor bank. The detectors operate light sources. The light emitted by the light sources is sensed by light sensors comprising light guides. The Titus system, however, has a Euse connected in series with each capacitor such that a failure or a capacitor blows a fuse isolating the failed capacitor and resulting in an over-voltage on that section of capacitors. When the over-vo~tage is detected, the detector actuates a light source. Such a system, however, is directed for its use in high voltage alternating current transmission systems and not for high voltage direct current system and therefore may be subject to the complications outlined hereinabove.
It is therefore a feature of the present invention to provide an alarm and control system for a capacitor bank connected in shunt circuit relation with a high voltage power supply.
Briefly, the present invention provides alarm and control system for a capacitor bank wherein the capacitox bank is connected in shunt circuit relation Case 2512 with the high voltage power supply. The capacitor bank comprises a plurality of groups of capac:itors connected in series where the capacitors of each group are connected in parallel. The alarm and control system includes a plurality of branch circuits each of which includes a grading resistor and a light source connected in series. The light source emits light in response to electrical current passing therethrough.
Each of the branch circuits is connected in parallel with a respective one of the capacitor groups. In the event of either a short circuit or low impedance condition being present in one of the capacitor of a capacitor group, flow of electrical current will bypass the branch circuit connected across this capacitor group. This results in no light being emitted from the light source of that branch circuit. The system includes a converter means which converts the light emitted from the light sources into corresponding electrical signals and a control means which is responsive to the~electrical signals. The control means generates an alarm signal when all but a predetermined number of the electrical signals are present for a prede-termined time interval.
The alarm signal is generated only after the expiry of the predetermined time interval to ensure that the alarm signal is indicative of a failed capacitor in one of the capacitor groups and not a brief disturbance due to fluctuations in the dc voltage.
It should be unders~ood that when an alarm signal has been generated by the alarm and control system such a signal may result in a human operator discontinuing power transmission from the power supply or in the automatic discontinuation of power from the power supply. Accordingly, the control means of the alarm and control system may further generate a control signal when all but the predetermined number of electrical Case 2512 signals are present for the predetermined time interval.
In this instance, the power supply would be responsive to the control signal to discontinue power transmissio~.
At this time, the switch means can be opened to effect removal of the capacitor bank out of shunt circuit relation with the power supply. Alternatively, the power supply may be responsive to the control signal to reduce dc voltage to the capacitor groups until such time as the transmission system can be shut down.
The power supply of the present invention may comprise an alternating current power supply, h~wever, preferably it comprises a high voltage direct current power convertor. It should be further understood that should a ground fault occur in the capacitor bank, then one or more of the light emitting sources may discontinue to emit light. The alarm control means will still generate an alarm signal but the converter means and control means of the system may recognize that more than one of the capacitors in the capacitor bank has failed and so recognizing may generate an alarm control signal after the expiry of a second predetermined time interval.
The converter means of the present invention may comprise a pattern recognition optical to digital converter including a scanning means or television camera and a micro processor. Such a scheme, however, is to be protected from the environment. Alternatively, the converter means may include light sensors and light guides.
In accordance with a broad aspect of the invention there is provided an alarm and control system for a capacitor bank,,the capacitor bank being connected in shunt circuit relation with a high voltage power supply, the capacitor bank comprising a plurality of serially connected groups of capacitors where the Case 2512 ca.pacitors of each group are connected in parallel circuit re].a-tion, the system comprising: a plurality of branch circuits each lncluding a grading resistor and a liyht source connec-ted in serial circuit relation, each of ~he branch circuits being connected in shunt circuit relation with a respective one of the capacitor yroups, the light source normally emitting light in response to the flow of electrical current therethrough, and the light source failing to emit light in the event that electrical current flow by-passes the respective branch circuit of the light source whereby one of a short circuit and low impedence condition is present in one capacitor of the respective one capacitor group;
converter means for converting only light emitted from the light sources into corresponding electrical signals;
and control means being responsive to the electrical signals to generate an alarm signal when all but a predetermined number of the electrical signals are present for a predetermined time interval.
For a better understanding of the nature and objects of the present invention, reference may be had to the accompanying diagrammatic drawing which is a schematic representation of an alarm and control system suitable for use in a high voltage direct
CAPACITOR BANK
The present invention relates to an alarm and control system for a capacitor bank. In partieular, it relates to alarm and control system for shunt eapaeitor banks connected across high voltage terminals of an electric power system.
Capaeitor banks suitable for use in hlgh voltage transmission commonly comprise a plurallty o parallel connected capacitors which form capacitor groups that are connected in series. The capaci-tor banks provide power factor correction for alternating current transmission and distribution cireuits. Also, the eapaeitor banks function as high voltage harmonic filters for power rectifiers and invertors of high voltage direct eurrent power transmission systems.
In the event that one or more capacitors of the capaeitor bank fail, it is imperative that such failures be detected; otherwise, the excess voltage made available by the failure of the capacitors may lead to the destruetion of a good number of the remaining funetioning capacitors in the capacitor bank.
Conventional means for detecting the failure of capaeitors in a capacitor bank, particularly when such eapacitor banks are utilized as high voltage direet current filters, comprise current differential, voltage differential and change in impedanee systems.
Case 2512 The detection of failed capacitors in a capacitor bank employed as a high vol-tage d~ filter, however, is complicated by the fact that the alternating harmonic current flow ~hrough the filter is relatively small and caries under no fault conditions as a function of such variables as ambient temperature, convertor firing angle and convertor current loading. These conventional detection means have difficulty in distinguishing between failed capacitors or variations in one or more o a combination of the above mentioned complications.
Another system for detecting the failure of a capacitor in a capacitor ban~ is disclosed in U.S.
Patent No. 3,973,169 which issued August 3, 1976, to Charles H. Titus. This system discloses an over voltage detector which is connected across each section of parallel capacitors in a capacitor bank. The detectors operate light sources. The light emitted by the light sources is sensed by light sensors comprising light guides. The Titus system, however, has a Euse connected in series with each capacitor such that a failure or a capacitor blows a fuse isolating the failed capacitor and resulting in an over-voltage on that section of capacitors. When the over-vo~tage is detected, the detector actuates a light source. Such a system, however, is directed for its use in high voltage alternating current transmission systems and not for high voltage direct current system and therefore may be subject to the complications outlined hereinabove.
It is therefore a feature of the present invention to provide an alarm and control system for a capacitor bank connected in shunt circuit relation with a high voltage power supply.
Briefly, the present invention provides alarm and control system for a capacitor bank wherein the capacitox bank is connected in shunt circuit relation Case 2512 with the high voltage power supply. The capacitor bank comprises a plurality of groups of capac:itors connected in series where the capacitors of each group are connected in parallel. The alarm and control system includes a plurality of branch circuits each of which includes a grading resistor and a light source connected in series. The light source emits light in response to electrical current passing therethrough.
Each of the branch circuits is connected in parallel with a respective one of the capacitor groups. In the event of either a short circuit or low impedance condition being present in one of the capacitor of a capacitor group, flow of electrical current will bypass the branch circuit connected across this capacitor group. This results in no light being emitted from the light source of that branch circuit. The system includes a converter means which converts the light emitted from the light sources into corresponding electrical signals and a control means which is responsive to the~electrical signals. The control means generates an alarm signal when all but a predetermined number of the electrical signals are present for a prede-termined time interval.
The alarm signal is generated only after the expiry of the predetermined time interval to ensure that the alarm signal is indicative of a failed capacitor in one of the capacitor groups and not a brief disturbance due to fluctuations in the dc voltage.
It should be unders~ood that when an alarm signal has been generated by the alarm and control system such a signal may result in a human operator discontinuing power transmission from the power supply or in the automatic discontinuation of power from the power supply. Accordingly, the control means of the alarm and control system may further generate a control signal when all but the predetermined number of electrical Case 2512 signals are present for the predetermined time interval.
In this instance, the power supply would be responsive to the control signal to discontinue power transmissio~.
At this time, the switch means can be opened to effect removal of the capacitor bank out of shunt circuit relation with the power supply. Alternatively, the power supply may be responsive to the control signal to reduce dc voltage to the capacitor groups until such time as the transmission system can be shut down.
The power supply of the present invention may comprise an alternating current power supply, h~wever, preferably it comprises a high voltage direct current power convertor. It should be further understood that should a ground fault occur in the capacitor bank, then one or more of the light emitting sources may discontinue to emit light. The alarm control means will still generate an alarm signal but the converter means and control means of the system may recognize that more than one of the capacitors in the capacitor bank has failed and so recognizing may generate an alarm control signal after the expiry of a second predetermined time interval.
The converter means of the present invention may comprise a pattern recognition optical to digital converter including a scanning means or television camera and a micro processor. Such a scheme, however, is to be protected from the environment. Alternatively, the converter means may include light sensors and light guides.
In accordance with a broad aspect of the invention there is provided an alarm and control system for a capacitor bank,,the capacitor bank being connected in shunt circuit relation with a high voltage power supply, the capacitor bank comprising a plurality of serially connected groups of capacitors where the Case 2512 ca.pacitors of each group are connected in parallel circuit re].a-tion, the system comprising: a plurality of branch circuits each lncluding a grading resistor and a liyht source connec-ted in serial circuit relation, each of ~he branch circuits being connected in shunt circuit relation with a respective one of the capacitor yroups, the light source normally emitting light in response to the flow of electrical current therethrough, and the light source failing to emit light in the event that electrical current flow by-passes the respective branch circuit of the light source whereby one of a short circuit and low impedence condition is present in one capacitor of the respective one capacitor group;
converter means for converting only light emitted from the light sources into corresponding electrical signals;
and control means being responsive to the electrical signals to generate an alarm signal when all but a predetermined number of the electrical signals are present for a predetermined time interval.
For a better understanding of the nature and objects of the present invention, reference may be had to the accompanying diagrammatic drawing which is a schematic representation of an alarm and control system suitable for use in a high voltage direct
2~ current power transmission system.
Referring now to the drawing an alarm and control system of the preferred embodiment is generally shown at 10 for a capacitor bank 12 which is connected by a switch means 14 in shunt circuit relation with a high voltage power supply 16. Additional capacitor banks 18 and 20 are shown connected by respective switch means 22 and 24 in shunt circuit relation with power supply 16. Each capacitor bank 12, ~ and ~ is shown in series relation with a tuning reactor 23.
Although only three capacitor banks are shown it should '713~
Case 2512 be understood that any number of capacitor banks may be used to provide the desired effect for the -transmission system. In -this instance capacitor banks 12, 18 and 20, along with respective tuning reactors 23, are acting as filters for the power supply which is shown to comprise a convertor control 26 and convertor 28. Convertor 28 draws its input ~rom a three phase al~ernating current transmission system 30 and generates ~ output through inductance 32 to a d.c. transmission system 34.
Although only one alarm and control system 10 is shown to operate in conjunction with capacitor bank 12, the capacitor banks 18 and 20 would have associated with each of them an alarm and control system similar to that used with capacitor bank 12.
Capacitor bank 12 is shown to comprise a plurality of serially connected groups of capacitors numbered 36A and 36B. Although only four groups of capacitors connected in series are shown it should be understood that any number of groups may be utilized as is desired to achieve the proper filtering for the transmission system. Each group of capacitors is shown to comprise individual capacitors 38 connected in parallel circuit relation. It should be understood that the number of capacitors 38 in each group of capacitors again is dependent upon the desired filtering effect to be achieved by capacitor bank.
The alarm and control system 10 is shown in the drawing to comprise a control means or controller 40, a converter means or converter 42 and a plurality oi-branch circuits 44A, 44B, 44C and 44D.
Branch circuits 44 while forming part of the alarm and control system also form part of the capacitor bank 12. For each oi~ the capacitor groups 36 there is a corresponding branch circuit 44 connected in shunt circuit relation therewith. ~ach of the branch '7:~
Case 2512 circuits ~4A through ~4D include a light source 46 and a grading resistor 48 connected in serial circuit relation. The grading resistor 4~ limits the current flow through its branch circuit. Each light source 46 emits light when electrical current passes therethrough. Failure of electrical current to pass through the light source is due to at least one capacitor in the corresponding capacitor group having either a short circuit or a low impedance condition. Thus, the failure of the light source to emit light may be an indication of a failed capacitor within the capacitor group. It should be understood that in the event that a plurality of light sources fail to emit light, this may be indicative of the presence of a ground fault in the capacitor bank.
Converter means or converter 42 converts light emitted from the light sources 46 into corresponding electrical signals which it outputs on lines 50 to controller 40. The converter is an optical to digital convertor and will include light sensors for each of the light sources. Controller 40 in response to the presence of the light signals at its input generates an alarm signal and a control signal when all but a predetermined number of the electrical signals are present for a predetermined time interval. The predetermined time interval is provided such that any variations in the d.c. voltage across the capacitor groups~
which may result in the failure of one or more light sources to emit light, will not result in an alarm signal or control signal. The predetermined number in this preferred embodiment is one. Thus when one source fails to emit light the control signal and alarm signal are generated along respective output lines 52 and 54 of controller 40. The control signal is fed to the convertor control 26 of power supply 16 which uses the '7~1 Case 2512 control signal to change the firing angle of convertor 28 such that no d.c. power will be transmitted on the syste~. 34. Once the transmissi.on of power on system 34 is discontinued, switch~means 14 may be opened and capacitor bank 12 removed rom the system 34. Since there is a plurality of capacitor banks in the system, the convertor control may then alter the Eiring angle of the convertox 28 to again bring about power transmission on the d.c. system 34.
The controller 40 comprises a logic circuit which further provides for the generation of a second control signal and second alarm signal along respective output lines 52 and 54 thereof in response to all but a second predetermined number of electrical signals being present for a second predetermined time interval.
In this event, the second predetermined number of electrical signals is a number greater than one and is indicative of a ground fault being present in the capacitor bank 12 for a second predetermined time interval. The second control signal is transmitted to the power supply 16 which functions in a manner similar to that of receiving the first control signal~
It should be understood that the predetermined time duration which is provided in the preferred embodiment bY the logic circuitry of controller 40, may be provided in the control circuitry of converter 42 in an alternate embodiment. Also, the logic circuit of control 40 may be arranged in any desired manner in order, for example, to provide alarm and annunciation for failure of a single capacitor unit failure, and the re-energization of a d.c. transmission circuit by means of a convertor control after the predetermined time interval has elapsed, in addition to a second alarm upon failure of a second capacitor unit.
Accordingly, it should be understood that alternate Case 2512 embodiments may be readily apparent to a man skilled in the art in light of the foregoing description.
Therefore, the present invention should only be limited to that which is claimed in the accompanying claims.
Referring now to the drawing an alarm and control system of the preferred embodiment is generally shown at 10 for a capacitor bank 12 which is connected by a switch means 14 in shunt circuit relation with a high voltage power supply 16. Additional capacitor banks 18 and 20 are shown connected by respective switch means 22 and 24 in shunt circuit relation with power supply 16. Each capacitor bank 12, ~ and ~ is shown in series relation with a tuning reactor 23.
Although only three capacitor banks are shown it should '713~
Case 2512 be understood that any number of capacitor banks may be used to provide the desired effect for the -transmission system. In -this instance capacitor banks 12, 18 and 20, along with respective tuning reactors 23, are acting as filters for the power supply which is shown to comprise a convertor control 26 and convertor 28. Convertor 28 draws its input ~rom a three phase al~ernating current transmission system 30 and generates ~ output through inductance 32 to a d.c. transmission system 34.
Although only one alarm and control system 10 is shown to operate in conjunction with capacitor bank 12, the capacitor banks 18 and 20 would have associated with each of them an alarm and control system similar to that used with capacitor bank 12.
Capacitor bank 12 is shown to comprise a plurality of serially connected groups of capacitors numbered 36A and 36B. Although only four groups of capacitors connected in series are shown it should be understood that any number of groups may be utilized as is desired to achieve the proper filtering for the transmission system. Each group of capacitors is shown to comprise individual capacitors 38 connected in parallel circuit relation. It should be understood that the number of capacitors 38 in each group of capacitors again is dependent upon the desired filtering effect to be achieved by capacitor bank.
The alarm and control system 10 is shown in the drawing to comprise a control means or controller 40, a converter means or converter 42 and a plurality oi-branch circuits 44A, 44B, 44C and 44D.
Branch circuits 44 while forming part of the alarm and control system also form part of the capacitor bank 12. For each oi~ the capacitor groups 36 there is a corresponding branch circuit 44 connected in shunt circuit relation therewith. ~ach of the branch '7:~
Case 2512 circuits ~4A through ~4D include a light source 46 and a grading resistor 48 connected in serial circuit relation. The grading resistor 4~ limits the current flow through its branch circuit. Each light source 46 emits light when electrical current passes therethrough. Failure of electrical current to pass through the light source is due to at least one capacitor in the corresponding capacitor group having either a short circuit or a low impedance condition. Thus, the failure of the light source to emit light may be an indication of a failed capacitor within the capacitor group. It should be understood that in the event that a plurality of light sources fail to emit light, this may be indicative of the presence of a ground fault in the capacitor bank.
Converter means or converter 42 converts light emitted from the light sources 46 into corresponding electrical signals which it outputs on lines 50 to controller 40. The converter is an optical to digital convertor and will include light sensors for each of the light sources. Controller 40 in response to the presence of the light signals at its input generates an alarm signal and a control signal when all but a predetermined number of the electrical signals are present for a predetermined time interval. The predetermined time interval is provided such that any variations in the d.c. voltage across the capacitor groups~
which may result in the failure of one or more light sources to emit light, will not result in an alarm signal or control signal. The predetermined number in this preferred embodiment is one. Thus when one source fails to emit light the control signal and alarm signal are generated along respective output lines 52 and 54 of controller 40. The control signal is fed to the convertor control 26 of power supply 16 which uses the '7~1 Case 2512 control signal to change the firing angle of convertor 28 such that no d.c. power will be transmitted on the syste~. 34. Once the transmissi.on of power on system 34 is discontinued, switch~means 14 may be opened and capacitor bank 12 removed rom the system 34. Since there is a plurality of capacitor banks in the system, the convertor control may then alter the Eiring angle of the convertox 28 to again bring about power transmission on the d.c. system 34.
The controller 40 comprises a logic circuit which further provides for the generation of a second control signal and second alarm signal along respective output lines 52 and 54 thereof in response to all but a second predetermined number of electrical signals being present for a second predetermined time interval.
In this event, the second predetermined number of electrical signals is a number greater than one and is indicative of a ground fault being present in the capacitor bank 12 for a second predetermined time interval. The second control signal is transmitted to the power supply 16 which functions in a manner similar to that of receiving the first control signal~
It should be understood that the predetermined time duration which is provided in the preferred embodiment bY the logic circuitry of controller 40, may be provided in the control circuitry of converter 42 in an alternate embodiment. Also, the logic circuit of control 40 may be arranged in any desired manner in order, for example, to provide alarm and annunciation for failure of a single capacitor unit failure, and the re-energization of a d.c. transmission circuit by means of a convertor control after the predetermined time interval has elapsed, in addition to a second alarm upon failure of a second capacitor unit.
Accordingly, it should be understood that alternate Case 2512 embodiments may be readily apparent to a man skilled in the art in light of the foregoing description.
Therefore, the present invention should only be limited to that which is claimed in the accompanying claims.
Claims (9)
1. An alarm and control system for a capacitor bank, said capacitor bank being connected in shunt circuit relation with a high voltage power supply, said capacitor bank comprising a plurality of serially connected groups of capacitors where the capacitors of each group are connected in parallel circuit relation, said system comprising:
a plurality of branch circuits each including a grading resistor and a light source connected in serial circuit relation, each of said branch circuits being connected in shunt circuit relation with a respective one of said capacitor groups, said light source normally emitting light in response to the flow of electrical current therethrough, and said light source failing to emit light in the event that electrical current flow by-passes the respective branch circuit of said light source whereby one of a short circuit and low impedence condition is present in one capacitor of said respective one capacitor group;
converter means for converting only light emitted from the light sources into corresponding electrical signals; and, controls means being responsive to said electrical signals to generate an alarm signal when all but a predetermined number of said electrical signals are present for a predetermined time interval.
a plurality of branch circuits each including a grading resistor and a light source connected in serial circuit relation, each of said branch circuits being connected in shunt circuit relation with a respective one of said capacitor groups, said light source normally emitting light in response to the flow of electrical current therethrough, and said light source failing to emit light in the event that electrical current flow by-passes the respective branch circuit of said light source whereby one of a short circuit and low impedence condition is present in one capacitor of said respective one capacitor group;
converter means for converting only light emitted from the light sources into corresponding electrical signals; and, controls means being responsive to said electrical signals to generate an alarm signal when all but a predetermined number of said electrical signals are present for a predetermined time interval.
2. The system of claim 1 wherein a switch means connects said capacitor bank in shunt circuit relation with said power supply, and said control means further generates a control signal when all but the predetermined number of said electrical signals are present for the predetermined time interval, said power Case 2512 supply being responsive to said control signal to discontinue power transmission such that the switch means may be opened to effect removal of said capacitor bank out of shunt circuit relation with said power supply.
3. The system of claim 2 wherein said power supply comprises a high voltage direct current power convertor.
4. The system of claim 1 wherein the electrical signals are present at the converter means for the predetermined time interval prior to transmission to said control means.
5. The system of claim 1 wherein the electrical signals are present at said controls means for said predetermined time interval.
6. The system of claim 1 wherein the control means generates a second alarm signal indicative of a ground fault in said capacitor bank when all but a second predetermined number of said electrical signals are present fro a second predetermined time interval.
7. The system of claim 2 wherein the control means generates the control signal and a second alarm signal indicative of a ground fault in said capacitor bank when all but a second predetermined number of said electrical signals are present for a second predetermined time interval.
8. The system of claim 1 wherein a switch means connects said capacitor bank in shunt circuit relation with said power supply and said control means further generates a control signal when all but the predetermined number of said electrical signals are present for the predetermined time interval, said power supply being responsive to said control signal to reduce the d.c. voltage to said capacitor groups.
Case 2512
Case 2512
9. The system of claim 7 wherein the first predetermined number is one and the second predetermined number is a number greater than one.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000370912A CA1158711A (en) | 1981-02-13 | 1981-02-13 | Alarm and control system for high voltage capacitor bank |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000370912A CA1158711A (en) | 1981-02-13 | 1981-02-13 | Alarm and control system for high voltage capacitor bank |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1158711A true CA1158711A (en) | 1983-12-13 |
Family
ID=4119197
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000370912A Expired CA1158711A (en) | 1981-02-13 | 1981-02-13 | Alarm and control system for high voltage capacitor bank |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1158711A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998026299A1 (en) * | 1996-12-12 | 1998-06-18 | Siemens Aktiengesellschaft | Device to detect the state of n power capacitors forming part of a high-voltage power capacitor bank |
| US6426899B1 (en) | 1997-12-15 | 2002-07-30 | Infineon Technologies Ag | Integrated memory with a buffer circuit |
| US20100085667A1 (en) * | 2007-05-10 | 2010-04-08 | Jalal Hallak | Circuit arrangement comprising at least two capacitors connected in series |
-
1981
- 1981-02-13 CA CA000370912A patent/CA1158711A/en not_active Expired
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998026299A1 (en) * | 1996-12-12 | 1998-06-18 | Siemens Aktiengesellschaft | Device to detect the state of n power capacitors forming part of a high-voltage power capacitor bank |
| US6426899B1 (en) | 1997-12-15 | 2002-07-30 | Infineon Technologies Ag | Integrated memory with a buffer circuit |
| US20100085667A1 (en) * | 2007-05-10 | 2010-04-08 | Jalal Hallak | Circuit arrangement comprising at least two capacitors connected in series |
| US8705214B2 (en) * | 2007-05-10 | 2014-04-22 | Siemens Aktiengesellschaft | Circuit arrangement comprising at least two capacitors connected in series |
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