Analysis of dual intelligent terminal anti-jump circuit in intelligent substation

Fan Hongtao and Zhang Yonggang, researchers of Xiangyang Power Supply Company of State Grid, pointed out in the 2nd issue of Electrical Technology in 2016 that in 220kV intelligent substations, 220kV circuit breakers are generally equipped with dual intelligent terminals, which are equivalent to two sets of independent operating boxes.

Compared with the conventional single operation box with double jump function, the anti-jump loop is realized in a different way. Based on the analysis of the anti-jump loop of the conventional operating box, this paper puts forward a method to realize the dual-intelligent terminal anti-jump loop.

According to the "12th Five-Year" power grid development plan of State Grid Corporation, the newly built substations with 110kV and above voltage levels are all intelligent substations, and the traditional integrated substations will be gradually transformed into intelligent substations. The 220kV circuit breaker of intelligent substation is generally equipped with dual intelligent terminal. The function of the dual intelligent terminal in the operation circuit is equivalent to two sets of independent operating boxes.

Compared with the traditional single operation box with double hop function, the independence of the operation loop of the dual intelligent terminal is stronger. It is stipulated in article 8.1.2 of Q/GDW161-2007 Code for Standardized Design of Line Protection and Auxiliary Devices that the anti-jump function of circuit breakers should be realized by the circuit breaker body mechanism.

Therefore, in accordance with the requirements of the high voltage circuit breaker related standards and specifications, the new factory 220kV circuit breaker body is equipped with anti-jump circuit, the anti-jump circuit of the operating box is usually not used. However, in the process of intelligent reconstruction of some old integrated stations, it is found that many old circuit breaker bodies do not have the function of anti-jump. The anti-jump function of such circuit breaker must be realized by intelligent terminal.

1. Principle analysis of anti-jump loop with traditional double-jump operating box

The function of anti-jump circuit is: when the hand or coincide to the fault, and the closing pulse is longer, or the closing contact is stuck dead, in order to prevent the circuit breaker to open and many times after closing, resulting in circuit breaker damage, so with anti-jump circuit. The operating box used by the traditional 220kV circuit breaker mechanism has two component phase trip circuit and one component phase closing circuit. The operation principle of the anti-jump loop of the operating box is shown in Figure 1 (the loop is properly simplified). When the hand closes or coincides with the fault and the circuit breaker trips, the TJa is connected, the 11TBIJa trip of the trip loop is maintained, the 12TBIJa(22TBIJa is the second group of trip) contact is closed and 1TBUJa is started. After 1TBUJa operation, 2TBUJa will start, and 2TBUJa will self-maintain in the presence of closing pulse through its own contacts, so that the normally closed contacts of the two groups of relays connected to the closing circuit will be disconnected, and the closing circuit will be cut off to avoid multiple jumping of the circuit breaker. Through the above analysis, we can see that the two groups of trip circuits have anti-jump function.

2 Dual intelligent terminal anti-jump circuit characteristics

The 220kV circuit breaker of intelligent substation is equipped with dual intelligent terminals, and both sets of intelligent terminals have independent and perfect jump circuit. Because the circuit breaker has only one combination of gate coil, so in cooperation with the circuit breaker mechanism, the first set of intelligent terminal main function for the first group of tripping and closing; The main function of the second set of intelligent terminal is the second group of tripping, and the first group of operating boxes are independent of each other, its closing circuit function is not used.

Therefore, the realization of the anti-jump function of the second group tripping circuit is very different from that of the single operating box. As shown in Figure 2, we first analyze the anti-jump loop of the first set of intelligent terminals, and its implementation method is as follows: When the trip pulse exists (TJa is switched on) or hand part, and the closing pulse does not return, the TBJa or hand jump contact STBJa connected in the trip circuit is switched on, and the anti-jump relay 1TBJUa is started. The normally open contact of 1TBJUa is switched on and self-maintained, and the normally closed contact is disconnected from the closing circuit to realize the first set of intelligent terminal anti-jump function.

However, when the second set of intelligent terminal trip, because the circuit breaker closing circuit is connected to the first set of intelligent terminal, and the second set of trip circuit and the first set of intelligent terminal independent, so the closing circuit of the anti-jump relay 1TBJUa will not start, its anti-jump function will not be realized.