JP2009201177A - Tap switching controller of transformer in substation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate overload by preventing generation of a cross current when reserve machine is turned on. <P>SOLUTION: A bus voltage regulator 47a determines parallel operation when each on-load tap changing transformer is connected to the same secondary bus by open/close state of a circuit breaker LS on the secondary of each on-load tap changing transformer and a bus tie circuit breaker, and performs tap change of respective on-load tap changing transformers operating in parallel in response to a command from a voltage regulation relay 48. At the same time, when an auxiliary relay X2 in the bus voltage regulator 47a is excited, and an electromagnetic contactor 54 connected with a circuit breaker 44 on the secondary of a reserve on-load tap changing transformer 21 interrupted from the secondary bus is turned on while an electromagnetic contactor 55 is turned off as if the circuit breaker 44 is turned on, a decision is made that the reserve on-load tap changing transformer 21 is operating in parallel with other on-load tap changing transformer, and tap change is performed simultaneously with other on-load tap changing transformer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a transformer tap change control device, and particularly in a substation having a plurality of on-load tap change transformers, one unit is not used as a spare unit, and a fault occurs in an operating transformer. When a healthy transformer is overloaded when it is disconnected from the grid, it relates to a transformer tap switching control device in a substation where a spare machine is connected to the grid to eliminate the overload. is there.

  FIG. 2 shows a normal system configuration of a substation having a plurality of conventional load-tap switching transformers. 1a is a primary A bus, 1b is a primary maiden bus, 2a is a secondary A bus, and 2b is a secondary. Otomo Line. The primary A bus 1a and the primary B bus 1b are connected via the closed LSs 7 and 9 and the closed bustie circuit breaker 8. The connection point of LS3, 4 is connected to the primary side of the on-load tap change transformer 15 of # 1B through the closed primary side circuit breaker 14, and similarly, the connection point of LS5, 6 is the primary state of the closed state. Is connected to the primary side of the # 2B on-load tap change transformer 17 via the side circuit breaker 16, and the connection point of the LSs 10 and 11 is switched to the # 3B on-load tap change via the closed primary side circuit breaker 18. It is connected to the primary side of the transformer 19 and the connection point of the LSs 12 and 13 is connected to the primary side of the on-load tap switching transformer 21 of # 4B, which is a spare machine, via the closed primary side circuit breaker 20. Further, the voltages of the primary A bus 1a and the primary B bus 1b are taken out through the transformers 22 and 23.

  On the other hand, the secondary upper bus 2a and the secondary second bus 2b are connected via the closed LSs 34 and 36 and the closed bustie circuit breaker 35. The connection point of LS24, 25 is connected to the secondary side of the on-load tap switching transformer 15 via the closed secondary side circuit breaker 41. Similarly, the connection point of LS26, 27 is the closed secondary side. It is connected to the secondary side of the on-load tap switching transformer 17 via the circuit breaker 42, and the connection point of the LSs 37 and 38 is connected to the secondary side of the on-load tap switching transformer 19 via the closed secondary side circuit breaker 43. The connection point of the LS 39, 40 is connected to the secondary side of the on-load tap switching transformer 21 via the automatic closing open secondary side circuit breaker 44. Moreover, each connection point of LS28, 29, 30, 31, 32, 33 is connected to load. The voltage of the buses 2a and 2b is taken out through the transformers 45 and 46.

  In the substation having the above-described configuration, when the # 4B on-load tap change transformer 21 is used as a spare machine, the three on-load tap change transformers 15, 17 and 19 of # 1B to # 3B provide secondary The load connected to the maiden buses 2a and 2b is shared. At this time, if an accident occurs in the secondary bus 2a, as shown in FIG. 3, the breaker 35 of the bus tie, the breaker 41 on the secondary side of the tap switching transformer 15 of # 1B, and the load tap of # 3B The circuit breaker 43 on the secondary side of the switching transformer 19 is opened, the secondary bus 2a goes out of power, and the # 2B on-load tap switching transformer 17 connected to the secondary bus 2b as shown by the arrow. The load on the secondary maiden bus 2b is concentrated on the 2nd bus line and may be overloaded. For example, if the load of the secondary bus 2a before the accident is equivalent to one transformer and the load of the secondary O-bus 2b is equivalent to the load of two transformers, # 2b on-load tap switching The load corresponding to two transformers is applied to the device 17. Therefore, the secondary circuit breaker 44 of the # 4B on-load tap change transformer 21 of the spare machine is turned on, and the load is distributed by using the # 2B and # 4B on-load tap change transformers 17 and 21 together. Then, the overload state of # 2B can be eliminated.

Note that prior art document information relating to the invention of this application includes the following.
Japanese Patent Laid-Open No. 62-40026 Japanese Patent Laid-Open No. 9-261869

  In general, when a plurality of on-load tap switching transformers are operated in parallel, if the tap positions are different, the output voltages are also different, and a cross current is generated between the transformers. For this reason, it is necessary to operate by matching the tap positions of the on-load tap switching transformers. Therefore, when the secondary bus voltage changes, the voltage regulation relay operates to maintain the secondary bus voltage appropriately, and the transformer taps in operation are operated simultaneously. The voltage regulating relay is provided separately from the devices shown in FIGS. Here, since the on-load tap switching transformer 21 of the spare machine # 4B is not operated in parallel, it becomes a tap position different from the other on-load tap switching transformers 15, 17, 19 during operation. When the secondary side circuit breaker 44 of the tap switching transformer 21 is turned on when the machine is loaded, a cross current may be generated and the overload may not be eliminated. Accordingly, the on-load tap switching transformer 21 of the spare machine is also tapped simultaneously with the other on-load tap switching transformers 15, 17, 19 during operation, and the tap position is always set to the other on-load tap switching transformers 15, 17,. By combining with 19, the on-load tap switching transformer 21 of the spare unit can be placed in parallel with the other on-load tap switching transformers 15, 17, 19.

  The present invention has been made to solve the above-described problems. The tap switching transformer of the spare machine is tapped simultaneously with the on-load tap switching transformer during operation, and the tap position is always aligned. Therefore, it is an object of the present invention to provide a transformer tap switching control device in a substation that can prevent the occurrence of a cross current when a spare machine is turned on and can eliminate an overload.

  According to a first aspect of the present invention, there is provided a transformer tap switching control apparatus for a transformer station, wherein a primary side circuit breaker of a plurality of on-load tap switching transformers including a spare on-load tap switching transformer, In addition, the secondary side of each load tap change transformer is connected to the secondary buses via the secondary circuit breaker, LS and bustie circuit breakers. In the transformer tap switching control device in the substation, the voltage adjustment command means for generating a voltage adjustment command according to the detected secondary bus voltage, the secondary circuit breaker of each load tap switching transformer, It is determined whether or not each load tap switching transformer is connected to the same secondary bus depending on the open / closed state of the LS and bus tie circuit breakers. If it is connected to the same secondary bus, it is determined that parallel operation is in progress. Parallel operation format Means, tap switching means for performing tap switching of each on-load tap switching transformer operating in parallel according to the command of the voltage adjustment command means, and a spare on-load tap switching transformer that is disconnected from the secondary bus Is connected to the secondary bus and includes means for making it appear to be operated in parallel with the on-load tap change-over transformer.

  As described above, according to the first aspect of the present invention, when the secondary bus voltage changes, the voltage adjustment command means generates a voltage adjustment command in response thereto. On the other hand, the parallel operation judging means is configured such that each load tap change transformer is connected to the same secondary bus depending on the open / close state of the secondary circuit breaker, LS and bustie breaker of each load tap change transformer. If it is connected to the same secondary bus, it is determined that parallel operation is in progress. The tap switching means performs tap switching of the on-load tap switching transformers operating in parallel according to the command of the voltage adjustment command means. The spare on-load tap switching transformer that is disconnected from the secondary bus is not normally considered to be in parallel operation by the parallel operation judging means, but this spare on-load tap switching transformer is connected to the secondary bus. Since there is means to make it appear that it is operating in parallel with the on-load tap change transformer during operation, the spare load tap change transformer is also tapped at the same time as the on-load tap change transformer. The tap position is always the same. For this reason, when the secondary side circuit breaker of the spare tap switching transformer is turned on, a cross current does not occur, and the overload is surely eliminated.

    The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram of a transformer automatic control device 47 including a state input circuit 47b of a spare on-load tap switching transformer 21 in the bus voltage regulator 47a. The system configuration of the substation is as shown in FIG. A voltage adjustment relay (voltage adjustment command means) 48 provided separately receives the detected voltages of the secondary buses 2a and 2b, and generates a voltage adjustment command for the bus voltage regulator 47a according to the voltages. The bus voltage regulator 47a is configured to open and close the secondary circuit breakers 41 to 44, the secondary side LSs 24 to 34, 36 to 40, and the bus tie circuit breaker 35 of each of the on-load tap change transformers 15, 17, 19, and 21. (In FIG. 1, only the open / close state of the secondary side of the on-load tap change transformer 21 is taken in via the control power supply 49 and the magnetic contactors 50 to 55. Similarly, it is determined whether or not the on-load tap switching transformers 15, 17, 19, and 21 are connected to the same secondary buses 2a and 2b. . That is, the bus voltage regulator 47a determines that the on-load tap switching transformers 15 and 19 are connected to the secondary A bus 2a when the secondary circuit breakers 41 and 43 and the LSs 24 and 37 are closed. Further, since the secondary circuit breaker 42 and the LS 27 are in the closed state, it is determined that the on-load tap switching transformer 17 is connected to the secondary O2 bus 2b, and the LS 34, 36 and the busty circuit breaker 35 are further determined. Is in the closed state, it is determined that the secondary AO bus 2a, 2b is connected, and the on-load tap change transformers 15, 17, 19 are connected to the same secondary bus and are in parallel operation. Judge that there is. Then, in response to a voltage adjustment command being issued from the voltage adjustment relay 48, the bus voltage adjustment device 47a simultaneously performs a tap switching operation on each of the on-load tap switching transformers 15, 17, 19 in parallel operation. Do.

  On the other hand, when the transformer automatic control device 47 is used, the contact of the auxiliary relay X1 is turned on, thereby turning on the auxiliary relay X2 in the bus voltage regulator 47a. The contact of this auxiliary relay X2 is connected to the state input circuit of the circuit breaker 44 in the state input circuit 47b on the secondary side of the on-load tap switching transformer 21, the electromagnetic contactor 54 (52a) is turned on, and the electromagnetic contactor 55 ( By turning off 52b), the bus voltage regulator 47a determines that the circuit breaker 44 is in a closed state and makes it appear that the on-load tap change transformer 21 is connected to the secondary bus. As a result, the on-load tap switching transformer 21 actually has the circuit breaker 44 in the open state and is not connected to the secondary bus, but the bus voltage regulator 47a has the circuit breaker 44 in the closed state. It is determined that the tap switching transformer 21 is connected to the secondary bus, and is determined to be operating in parallel with the other on-load tap switching transformers 15, 17, 19, and the voltage adjustment command of the voltage adjustment relay 48 is Accordingly, tap switching is performed simultaneously with the other on-load tap switching transformers 15, 17, and 19. The state input circuit 47b also receives the state of the LS on the secondary bus 2a side and the LS on the second bus line 2b side of the on-load tap switching transformer 21.

  According to the preferred embodiment, the same secondary bus can be obtained by pretending that the on-load tap switching transformer 21 of the spare machine that is actually disconnected from the secondary bus is connected to the secondary bus. It looks like it is operating in parallel with other connected on-load tap change transformers 15, 17, 19, and other on-load tap change transformers 15, 17, At the same time as 19, tap switching is performed. As a result, the tap position of the spare on-load tap change transformer 21 always coincides with the other on-load tap change transformers 15, 17, 19 in parallel operation. For this reason, the secondary side circuit breaker 44 of the spare on-load tap switching transformer 21 can be quickly turned on, and when the secondary side circuit breaker 44 is turned on, other on-load tap switching in parallel operation is performed. Since the transformers 15, 17, and 19 are aligned with the tap positions, no cross current is generated and the overload can be reliably eliminated.

1 is a circuit diagram of a transformer automatic control device including a bus voltage regulator according to an embodiment of the present invention. FIG. It is a system | strain block diagram at the time of normal of the substation which has the some conventional tap change transformer at the time of a load. It is a system | strain block diagram after the accident removal of the substation which has the conventional several tap change transformer at the time of a load.

Explanation of symbols

1a, 1b ... primary bus 2a, 2b ... secondary bus 3-7, 9-13, 24-34, 36-40 ... LS
8, 35 ... Busty circuit breaker 14, 16, 18, 20, 41-44 ... Circuit breaker 47 ... Automatic transformer control device 47a ... Bus voltage regulator 47b ... State input circuit 48 ... Voltage regulation relay 50-55 ... Electromagnetic contact vessel

Claims (1)

  Connects the primary side of multiple load tap change transformers, including spare load tap change transformers, to the primary buses via the primary side circuit breaker, LS and bustie circuit breaker, and each load tap Detected secondary bus voltage in a transformer tap switching control device at a substation where the secondary side of the switching transformer is connected to a plurality of secondary buses via secondary circuit breakers, LS and bustie circuit breakers Depending on the voltage adjustment command means for generating a voltage adjustment command, and the on-load state of each load-side tap switching transformer is the same depending on the open / close state of the secondary side circuit breaker, LS and bustie circuit breaker of each load-time tap switching transformer. It is determined whether or not it is connected to the secondary bus, and if it is connected to the same secondary bus, it is operated in parallel according to the command of the parallel operation determination means and the voltage adjustment command means that determine that parallel operation is being performed. At each load Tap switching means for switching the tap of the switching transformer and a spare on-load tap switching transformer that is disconnected from the secondary bus are connected to the secondary bus and operated in parallel with the on-load tap switching transformer in operation. And a tap switching control device for a transformer in a substation.

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