JP5116607B2 - Gas circuit breaker - Google Patents

Description

  The present invention relates to a gas circuit breaker configured by connecting a closing resistance device in parallel with a breaker main contact.

  In the gas circuit breaker, a configuration is known in which a closing resistance device is connected in parallel with the breaker main contact in order to suppress a closing surge generated at the time of closing. The closing resistor device has a closing resistor and a closing contact connected in electrical series connection, and this closing contact is closed prior to the closing of the breaking main contact and connected by connecting the closing resistor to the main circuit. Surge is suppressed and the closing contact is opened prior to the opening of the breaker main contact to disconnect the closing resistor from the main circuit. The conventional gas circuit breaker is designed in consideration of the resistance value for suppressing the charging surge and the heat capacity during the charging operation when the charging resistor is manufactured. Also, in systems using gas circuit breakers, for example, in the case of usage in the United States, if the transmission line becomes long, the probability of continuous lightning strikes on the same transmission line increases, so a temporary accident such as a lightning strike In contrast, after a predetermined time has elapsed from the shut-off operation, a continuous throw-in operation is repeated in which the CO action (C is for turning on the breaker and O is for opening the breaker) is repeated as CO-CO-CO .... May do.

  By the way, in a gas circuit breaker having a charging resistance device, when performing a continuous charging operation that repeats the CO operation, a strict regulation of the elapsed time from the first CO operation to the second CO operation is performed. However, if this elapsed time is set short to increase the stability of the system, the next charging operation will be performed without the cooling resistor being sufficiently cooled, and the temperature rise of the charging resistor will be the physical temperature. There is a risk of reaching the limit value. Therefore, it is necessary to set the elapsed time between the CO operations in consideration of the cooling time of the charging resistor, but if this elapsed time is set as a long fixed value as in the conventional case, Stability is reduced.

   An object of the present invention is to provide a gas circuit breaker capable of shortening the elapsed time between CO operations while considering the cooling time of the charging resistor.

  In order to achieve the above object, the present invention provides a breaker main contact, a closing resistance device in which a closing resistor and a resistance contact are connected in series, and electrically connected in parallel to the blocking portion main contact, and the blocking An operation device that closes the resistance contact prior to the closing of the main contact and opens the resistance contact prior to the opening of the breaking main contact, and continuously turns on and off the operation device multiple times. In a gas circuit breaker provided with a control circuit for providing an operation signal, when the calculated operating temperature and the calculated operating temperature of the charging resistor are calculated, and when the calculated operating temperature reaches the preset upper limit allowable temperature threshold An operation for giving a closing lock signal for blocking a closing operation signal from the control circuit to the operation device, and for releasing the closing lock signal when the cooling calculation temperature reaches a preset lower limit allowable temperature threshold value. Part And wherein the digit.

  According to the gas circuit breaker according to the present invention, since the calculated operating temperature and the cooling calculated temperature of the charging resistor calculated by the calculation unit are managed by the upper limit allowable temperature threshold and the lower limit allowable temperature threshold, the temperature of the charging resistor The elapsed time between CO operations can be determined in consideration of the temperature of the input resistor while preventing the temperature from reaching the physical temperature limit. That is, the elapsed time between the CO operations is not always set to the same fixed value as in the conventional case, and can be adjusted in consideration of the rising temperature or cooling temperature of the input resistor each time. It is possible to extend the elapsed time so that a predetermined cooling time is given by giving an input lock signal in a situation where the upper limit allowable temperature threshold is exceeded, and an input lock signal is given in a situation below the upper limit allowable temperature threshold. Therefore, the elapsed time can be shortened compared to the previous case, and eventually the time required for the entire continuous charging operation can be shortened while considering the cooling time of the charging resistor.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block configuration diagram showing a schematic configuration of a gas circuit breaker according to an embodiment of the present invention.
The gas circuit breaker has a generally known configuration. For example, a breaker main contact 2 is disposed in a sealed container 1 filled with an arc extinguishing gas, and both ends of the breaker main contact 2 are connected to a bushing 3, 4 are connected to the central conductors 5 and 6. A closing resistor device in which a closing resistor 7 and a closing contact 8 are connected in series is connected in parallel with the interrupting section main contact 2 in the sealed container 1. Current transformers 9 and 10 are disposed below the bushings 3 and 4, respectively, and voltage transformers 11 and 12 are disposed on the airlines connected to the air external terminals of the bushings 3 and 4, respectively. . An operating device 13 that opens and closes the interrupter main contact 2 and the closing contact 8 is arranged near the outside of the hermetic container 1 and is configured to operate in response to a closing and shutting operation command from the control circuit 14. . In general, the gas circuit breaker takes in system signals from the current transformers 9 and 10 and the voltage transformers 11 and 12 and gives a command to the operating device 13 through the control circuit 14 to open and close the breaking unit.

  However, in the case of the continuous throwing operation in which the throwing operation is repeated many times, when the AND condition between the throwing operation command from the normal control circuit 14 and the command from the arithmetic unit 15 is satisfied, the throwing operation command is given to the controller 13. ing. That is, both current transformers 9 and 10 are used as current element acquisition means, and voltage transformers 11 and 12 are used as voltage element acquisition means, and current elements and voltage elements taken from these element acquisition means are used. A calculation unit 15 for performing calculation processing, which will be described in detail later, is newly added, and as a result of calculation processing from the calculation unit 15, a closing lock signal for blocking the closing operation, a release signal for canceling the closing locking signal, Is supplied to the control circuit 14, and in the state where this closing lock signal is given, the closing operation command is not given from the control circuit 14 to the operating device 13.

FIG. 2 is a time chart showing the open / close characteristics of the breaking unit main contact 2 and the making contact 8 and the temperature characteristic of the making resistor 7 described above.
As can be seen from the open / close characteristics shown in the figure, when a closing operation command is given from the control circuit 14 to the operating device 13 for the gas circuit breaker in the shut-off state, first, the time t1 prior to closing of the shut-off portion main contact 2 Then, the resistance contact 8 is closed and the closing resistor 7 is connected to the main circuit, and then the breaking portion main contact 2 is closed at time t3 after the preceding closing time tR. Thereafter, when the accident of the main circuit has not recovered, the control circuit 14 again gives a shut-off operation command to the gas circuit breaker, and the resistance contact 8 is opened at time t4, and then the shut-off main contact at time t5. 2 is opened. This is the first CO operation. After that, at time t6 when a predetermined elapsed time has passed, the input command is again given from the control circuit 14, and the second CO operation is performed.

  In particular, attention is paid here to the elapsed time between CO operations, for example, the elapsed time between CO operations (t6-t5) in the temperature characteristic curve A, which will be described in detail later. Strictly speaking, there is a time from when the closing operation command is given to when the resistance contact 8 is closed, but here, the description is simplified to show that the resistance contact 8 is closed at the same time that the closing operation command is given. ing. The elapsed time (t6-t5) between the CO operations has been a fixed value so far, but here it is set as a time that can be changed in consideration of the temperature characteristics of the input resistor 7.

The temperature characteristics of the making resistor 7 during such a continuous making operation are also shown in FIG.
The vertical axis indicates the temperature, and the temperature of the closing resistor 7 at time t1 when the resistance contact 8 is closed and the closing resistor 7 is connected to the main circuit is indicated as the base temperature T2. The base temperature T2 may be replaced with the measured temperature of the arc extinguishing gas in the sealed container 1 at the same time t1. In addition, the vertical axis indicates the upper limit allowable temperature threshold Tu and the lower limit allowable temperature threshold Td. The upper limit allowable temperature threshold Tu is a set value lower than the physical temperature limit value of the input resistor 7 and is applied for the first time. If the temperature of the input resistor 7 in operation is a temperature slightly lower than the upper limit allowable temperature threshold Tu, the input resistance even when the second input operation is performed after the elapse of a preset time (t6-t5). The temperature of the body 7 is a value that does not reach the physical temperature limit value. The lower limit allowable temperature threshold value Td is a value that can be achieved without the temperature of the making resistor 7 reaching the physical temperature limit value even when the second making operation is performed from this temperature, and is higher than the base temperature T2. . Further, the temperature rise curve of the making resistor 7 at the preceding making time tR is shown in a simplified manner.

  A temperature characteristic curve A shows a temperature transition when a relatively small current I flows through the input resistor 7. When the current I is small, the energy injected into the making resistor 7 is small, and the temperature of the making resistor 7 rises as a temperature characteristic curve A as shown by a solid line. In the first turning-on operation, the first peak temperature is substantially reached at time t3 when the breaker main contact 2 is closed, but does not reach the preset upper limit allowable temperature threshold Tu. Since most of the current I flows through the breaker main contact 2 after time t3 when the breaker main contact 2 is closed, the input resistor 7 is cooled by the arc extinguishing gas.

  After that, when the interrupting operation is performed at the interrupting unit main contact 2 at time t5 and the input resistor 7 is connected to the main circuit again at time t6 after a predetermined elapsed time has elapsed, the temperature characteristics are restarted from that time. Curve A shows a temperature rise, and reaches the second peak temperature when the breaker main contact 2 is closed approximately at time t8. Since the temperature at time t6 is slightly higher than the base temperature T2 at the previous time t1, the second peak temperature at the time t8 is higher than the first peak temperature at the previous time t3. However, the upper limit allowable temperature threshold Tu has not yet been reached. Therefore, the temperature rise of the charging resistor 7 does not cause a problem even if the continuous charging operation is performed twice continuously under the system conditions and elapsed time described above.

  However, when the current I increases due to lightning or the like, the temperature transition of the input resistor 7 changes as a temperature characteristic curve B. In this case, the energy injected into the making resistor 7 becomes larger than in the previous case, and the temperature rise of the making resistor 7 becomes a problem. That is, the first peak temperature is reached at the time t3 when the breaker main contact 2 is closed, and the temperature of the closing resistor 7 has already exceeded the upper limit allowable temperature threshold Tu at this time. Nevertheless, after time t3 when the interrupting section main contact 2 is closed, most of the current I flows through the interrupting section main contact 2, and the charging resistor 7 is cooled by the arc extinguishing gas.

  Thereafter, the breaking operation is performed at the breaker main contact 2 at time t5. Thereafter, as in the case where the current I is small, the charging resistor 7 is again turned on at time t6 after the elapse of a predetermined initial elapsed time. When connected to the circuit, the temperature rises again from that point, and since the first peak temperature has already exceeded the upper limit allowable temperature threshold Tu at time t3, the second peak temperature at time t8 remains as it is. The physical temperature limit is reached. Such a phenomenon occurs not only when the current I is increased, but also when the number of continuous input operations is increased.

  Therefore, the temperature transition of the charging resistor 7 is monitored as shown by the temperature characteristic curve C by the processing of the calculation unit 15 to control the elapsed time between the CO operations. That is, when the temperature of the making resistor 7 exceeds the upper limit allowable temperature threshold Tu during the first making operation, the resistance contact 8 is not closed at time t6 during the second making operation as shown in the temperature characteristic curve B. The operation unit 15 performs delay control so as to close the resistance contact 8 at a later time t7. The elapsed time between the CO operations in this case is a delay elapsed time (t7-t5) that is longer than the initial setting time (t6-t5). During this extension time, the charging resistor 7 is cooled by the arc extinguishing gas in the sealed container 1, and at time t7, the temperature is cooled to the lower limit allowable temperature threshold Td, and thereafter The second CO operation is started and the resistance contact 8 is closed.

  As can be seen from this description, in the case of a continuous charging operation in which the CO operation is repeated many times, the elapsed time between the CO operations is not set to a fixed value as in the conventional case, but the CO operation is performed according to the system condition and the number of continuous charging operations. It is desirable to change the elapsed time between.

  In order to realize this, the upper limit allowable temperature threshold Tu and the lower limit allowable temperature threshold Td are set as the temperatures of the input resistor 7, and the injection energy into the input resistor 7 and the temperature of the input resistor 7 according to the system conditions are set. A calculation unit 15 that performs prediction calculation is provided. Further, the calculation unit 15 calculates that the upper limit allowable temperature threshold Tu has been reached at time t2 as in the temperature characteristic curve C described above, and calculates that the lower limit allowable temperature threshold Td has been reached at time t7. I do. As a result, when the calculation unit 15 calculates that the upper limit allowable temperature threshold value Tu has been reached, a closing lock signal is given from the calculation unit 15 to the control circuit 14, and a closing operation command is sent from the control circuit 14 to the operating device 13 alone. Stop being given. On the other hand, when it is calculated that the lower limit allowable temperature threshold value Td has been reached, a release signal for releasing the above-described lock signal is given to the control circuit 14 so that a closing operation command is given from the control circuit 14 to the operating device 13. ing.

Next, details of the processing in the calculation unit 15 will be described.
FIG. 2 is a flowchart showing a processing procedure in the calculation unit 15. First, in step S1, the current element I taken from the current transformers 9, 10 and the voltage element V1 taken from the voltage transformers 11, 12, etc. , V <b> 2 is used to calculate the inter-pole resistance value R of the blocking portion. In step S2, in order to determine that the closing resistor 7 is connected to the main circuit, the calculated inter-electrode resistance value R is compared with the preset closing period identifying thresholds R1 and R2. If it is within that range, it is determined that the input resistor 7 has been inserted into the main circuit. The above-described preceding charging period identifying thresholds R1 and R2 are set in consideration of the resistance value of the charging resistor 7 so that it can be distinguished from other situations that the charging resistor 7 is connected to the main circuit. Value.

  Although it can be detected that the input resistor 7 has been inserted into the main circuit by other methods, as described above, the interelectrode resistance value R is calculated from the current element I and the voltage elements V1 and V2. Has advantages. Since it is possible to detect not the time when the resistive contact 8 contacts but the time when the preceding discharge occurs at the resistive contact 8, the energy injected from the main circuit to the input resistor 7 to be described later can be calculated more precisely. can do.

  If it is detected by the determination in step S2 that the making resistor 7 has been inserted into the main circuit, in step S3, the temperature rise due to the injected energy from the main circuit in the making resistor 7 and the previous making operation described in detail later. The calculated temperature T1 during the rise is calculated from the calculated temperature T3 during cooling which is the remaining temperature at the time. The rise temperature due to the energy injected from the main circuit in the input resistor 7 includes the current element I taken from the current transformers 9 and 10, the voltage elements V 1 and V 2 taken from the voltage transformers 11 and 12, and the input resistance. The volume V of the body 7 and the volume specific heat Cv of the input resistor 7 are calculated. Further, the cooling calculation temperature T3, which is the remaining temperature at the previous charging operation, is considered to be sufficiently cooled to the temperature in the sealed container 1 if the current time is the first charging operation. It is equal to the explained base temperature T2.

  After that, in step S4, it is determined whether or not the calculated calculated operating temperature T1 of the charging resistor 7 exceeds the preset upper limit allowable temperature threshold Tu, and if it exceeds the upper limit allowable temperature threshold Tu, the calculation is performed in step S5. The unit 15 gives a closing lock signal to the control circuit 14. In response to this, the control circuit 14 blocks the input operation command to the operating device 13, and the input resistor 7 is not connected to the main circuit. In other words, referring to FIG. 2, when it is detected in step S4 that the upper limit allowable temperature threshold Tu has been exceeded at time t2 as in temperature characteristic curve B, the resistance contact 8 is detected at time t6 in step S5 as in temperature characteristic curve B. Is prevented from closing again.

  As shown in the temperature characteristic curve C shown in FIG. 2, the cooling of the closing resistor 7 which is started after the breaking contact main contact 2 is turned on at the time t3 after the turning on of the resistance contact 8 is monitored. The closing operation is continued until the lower limit allowable temperature threshold value Td is reached. The temperature at which the charging resistor 7 is cooled is calculated by the arithmetic expression shown in step S6. That is, the cooling calculation temperature T4 of the charging resistor 7 is the rising calculation temperature T1, the base temperature T2, and the closing resistor main contact 2 is closed at time t3 in FIG. It is calculated by the cooling elapsed time ta after that and the cooling time constant τ of the charging resistor 7. The calculation unit 15 compares the calculated cooling temperature T4 with the lower limit allowable temperature threshold Td in step S7, and is cooled to the lower limit allowable temperature threshold Td at time t7 along the temperature characteristic curve C shown in FIG. To monitor.

  In the temperature characteristic curve C of FIG. 2, when the time from the time t3 to the time t7 (t7-t3) is the cooling elapsed time ta, the cooling calculation temperature T4 becomes the lower limit allowable temperature threshold Td. When this is detected by the determination in step S7, in step S8, a release signal for releasing the above-mentioned lock signal is given to the control circuit 14. At this time, the AND condition of the making operation command is satisfied, and the control circuit 14 gives the making operation command to the operating device 13, and the second CO operation is started, which is later than the time t6 in FIG. Thus, the resistance contact 8 is closed. Then, in step S9, it is determined whether or not the predetermined number of continuous charging operations has been reached. If the number of continuous charging operations is two, the continuous charging operation is completed. The same state is maintained after operation. However, if the number of times is set so as to repeat the interlocking input operation, the same processing is repeated.

  In this way, when the current I is large as shown by the temperature characteristic curve C in FIG. 2, the time between the CO operations in the continuous charging operation is larger than when the current I shown by the temperature characteristic curve A in FIG. 2 is small. Increase time. This increases the cooling time given to the charging resistor 7, suppresses the temperature of the charging resistor 7 when the second CO operation is started, and reaches the physical temperature limit value in the second charging operation. Is prevented. In addition, since the temperature of the input resistor 7 is managed by the upper limit allowable temperature threshold Tu and the lower limit allowable temperature threshold Td, the cooling time is not unnecessarily prolonged as in the case of setting the expectation. Thus, the elapsed time following the CO operation time (t5-t1) is changed from the initial setting time (t6-t5) to the delay time (t7-t5) while preventing the charging resistor 7 from reaching the physical temperature limit value. As a result, the entire continuous charging operation can be performed in a short time.

  By the way, if it is determined in step S2 that the closing resistor 7 is not inserted into the main circuit, or the rising calculation temperature T1 of the closing resistor 7 is determined in advance in step S4, the upper limit allowable temperature threshold Tu. In the following cases, the process does not proceed to the above-described step S5, and the closing lock signal is not given to the control circuit 14, so that the continuous charging operation is continuously performed based on the elapsed time between the CO operations set in advance. Can do. At this time, in step S10, the cooling calculation temperature T3 is calculated using the same mathematical formula as the above-described cooling calculation temperature T4, and this cooling calculation temperature T3 is added in step S3 in the next operation of the continuous charging operation. To calculate the calculated operating temperature T1.

  The process of step S10 will be described again with the temperature characteristic curve A shown in FIG. For example, when the calculated temperature T1 during the rise at time t3 is equal to or lower than the upper limit allowable temperature threshold Tu, the charging resistor 7 is cooled by the arc extinguishing gas in the sealed container 1 from time t3. When the next operation of the continuous charging operation is performed at time t6, the cooling calculation temperature T3 is calculated with the elapsed time ta as (t6-t3) basically in the same formula as step S6, and at time t8 in step S3. When calculating the calculated temperature T1 when the second peak value is increased, the calculated temperature T3 during cooling is added to the increased temperature due to the injected energy. Thereafter, in step S4, it is determined whether or not the calculated temperature T1 when the second peak value rises exceeds the upper limit allowable temperature threshold Tu. As a result, when the second CO operation of the continuous charging operation is performed at time t6, the temperature of the charging resistor 7 is correctly reflected in the arithmetic processing. When the charging resistor 7 is sufficiently cooled, the cooling calculation temperature T3 is equal to the base temperature T2, and in this case, the temperature of the charging resistor 7 is correctly reflected in the calculation processing.

  Such processing in the calculation unit 15 can be utilized even when the current I is small as shown by the temperature characteristic curve A in FIG. That is, the cooling calculation temperature T3 at the previous operation remains, and the cooling calculation temperature T3 at this time is added to the rising calculation temperature T1 at the subsequent operation. When it is further determined that the upper limit allowable temperature threshold value Tu is exceeded at or near the peak value several times, a closing lock signal can be similarly given. Therefore, as in the previous case, the temperature rise of the input resistor 7 can be suppressed without the temperature of the input resistor 7 reaching the physical temperature limit value. In addition, since the temperature of the charging resistor 7 is managed by the upper limit allowable temperature threshold Tu and the lower limit allowable temperature threshold Td, the cooling time is continuously increased without unnecessarily increasing the time as expected. The entire charging operation can be performed in a short time.

  According to the gas circuit breaker described above, the calculation unit 15 that manages the calculated calculation temperature T1 during the rise and the calculation temperature T4 during the cooling by the preset upper limit allowable temperature threshold Tu and the lower limit allowable temperature threshold Td is provided. It is predicted that the input resistor 7 will reach the physical temperature limit value during the next CO operation by the temperature threshold Tu, and the input resistor 7 will not reach the physical temperature limit value during the next CO operation by the lower limit allowable temperature threshold Td. By predicting the point of time to be cooled, and by predicting both, it is possible to increase the cooling time by making the elapsed time between CO operations longer than usual, so regardless of the system conditions and the number of continuous charging operations, The elapsed time between the CO operations can be shortened while preventing the temperature of the charging resistor 7 from reaching the physical temperature limit value, so that the time required for the entire continuous charging operation can be shortened. .

  Particularly in the implementation of the present invention, as described above, in order to calculate the calculated operating temperature T1 at the time of rise, the current element I of the system and the voltage elements V1 and V2 are taken in, and the interpole resistance value R of the interrupting part is calculated. As a result, the time during which the main circuit load current flows through the making resistor 7 is reflected. For this reason, it is possible to detect the time point when the preceding discharge occurs at the resistance contact 8 and to calculate the injection energy given from the main circuit to the input resistor 7 more strictly. It is possible to more appropriately make a determination to give an input lock signal and a determination to give a release signal for releasing the input lock signal.

  Further, in the preferred embodiment, in calculating the calculated temperature T1 during the rise and the calculated temperature T4 during the cooling, the calculated temperature T3 during the cooling from the temperature remaining during the previous charging operation is added in step S10. The rising calculation temperature T1 and the cooling calculation temperature T4 can be calculated.

  The gas circuit breaker of the present invention is not limited to the gas circuit breaker having the bushings 3 and 4 on both sides as shown in FIG. 1, but can also be applied to a gas circuit breaker in a gas insulated switchgear.

It is a block block diagram which shows the whole structure of the gas circuit breaker by one embodiment of this invention. It is a time chart which shows the switching characteristic of the interruption | blocking part main contact shown in FIG. 1, and a closing contact, and the temperature characteristic of a making resistor. It is a flowchart which shows the process sequence of the calculating part shown in FIG.

Explanation of symbols

1 Sealed container 2 Breaker main contact 3, 4 Bushing 5, 6 Center conductor
7 Input resistor 8 Resistive contact 9, 10 Current transformer 11, 12 Voltage transformer 13 Controller 14 Control circuit 15 Calculation unit T1 Calculation temperature when rising T2 Base temperature T3 Calculation temperature when cooling Td Lower limit allowable temperature threshold Tu Upper limit allowable temperature Threshold

Claims (1)

  A breaking resistance main contact, a closing resistance device in which a closing resistor and a resistance contact are connected in series are electrically connected in parallel to the breaking portion main contact, and prior to the closing of the breaking portion main contact, Gas comprising an operating device that closes the resistive contact and opens the resistive contact prior to opening of the main contact of the interrupting section, and a control circuit that provides the operating device with a continuous input operation signal that repeats input and output operations a plurality of times. In the circuit breaker, the rising operation temperature and the cooling operation temperature of the closing resistor are calculated, and when the rising operation temperature reaches a preset upper limit allowable temperature threshold, the closing operation from the control circuit to the operating device A gas shutoff characterized by providing a lock signal for blocking the signal and providing a calculation unit for canceling the lock signal when the calculated operating temperature during cooling reaches a preset lower limit allowable temperature threshold value vessel.

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