Analysis of anti-jump circuit of dual intelligent terminals in smart substations

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


Compared with the conventional comprehensive self-station single operation box with double-hop function, its anti-jump loop implementation method is different. Based on the analysis of the anti-jump circuit of conventional operation boxes, this article proposes a method to implement dual intelligent terminal anti-jump circuits.


According to the "Twelfth Five-Year Plan" power grid development plan of the State Grid Corporation of China, all new substations with voltage levels of 110kV and above are intelligent substations, and traditional integrated substations will be gradually transformed into intelligent substations. The 220kV circuit breaker mechanism of an intelligent substation is generally equipped with dual intelligent terminals. The function of the dual intelligent terminals on the operating circuit is equivalent to two sets of independent operating boxes.


Compared with the traditional single operation box with double jump function, the dual intelligent terminal operation circuit is more independent. In Q/GDW161-2007 "Standardized Design Code for Line Protection and Auxiliary Devices", Article 8.1.2 stipulates that the anti-jump function of the circuit breaker should be realized by the circuit breaker body mechanism.


Therefore, in accordance with the requirements of relevant standards and specifications for high-voltage circuit breakers, the newly manufactured 220kV circuit breaker body is equipped with an anti-jump circuit, and the anti-jump circuit of the operation box is usually not used. However, during the intelligent transformation and construction of some old comprehensive substations, it was found that many older circuit breaker body bodies do not have anti-jump function. The anti-jump function of this type of circuit breaker must be implemented by intelligent terminals.


1 Analysis of the principle of anti-jump circuit with traditional double-jump operating box


The function of the anti-trip circuit is: when the manual closing or reclosing fails, and the closing pulse is long, or the closing contact is sticky, in order to prevent the circuit breaker from tripping and closing multiple times, causing damage to the circuit breaker, an anti-trip circuit is provided. Traditional The operation box used by the 220kV circuit breaker mechanism has two component-phase tripping circuits and one component-phase closing circuit. The action principle of the operation box anti-trip circuit is shown in Figure 1 (the circuit is appropriately simplified). When the circuit breaker trips when the circuit breaker is manually closed or reclosed, TJa is turned on, the 11TBIJa trip of the trip circuit is maintained, and the 12TBIJa (22TBIJa is the second group of trip) contacts are closed and started. 1TBUJa, 1TBUJa starts 2TBUJa after the closing pulse exists, and 2TBUJa self-maintains in the presence of the closing pulse, so the normally closed contacts of the two groups of relays connected in series to the closing circuit are disconnected, cutting off the closing circuit and preventing the circuit breaker from tripping multiple times. Through the above analysis, we can see that both sets of tripping circuits have anti-trip functions.


2 Features of dual intelligent terminal anti-bounce circuit


The 220kV circuit breaker of the intelligent substation is equipped with dual intelligent terminals. Both sets of intelligent terminals have independent and complete tripping and closing circuits. Because the circuit breaker has only one combination of switching coils, in cooperation with the circuit breaker mechanism, the main function of the first set of intelligent terminals is the tripping and closing of the first set; the main function of the second set of intelligent terminals is the tripping of the second set, and is independent of the first set of operation boxes, and its closing circuit function is not used.

Therefore, the implementation of the anti-trip function of the second set of trip circuits is very different from that of the single operation box. As shown in Figure 2, we first analyze the anti-trip circuit of the first set of intelligent terminals. The implementation method is: when the trip pulse exists (TJa is turned on) or the hands are separated, And when the closing pulse does not return, the TBJa or manual trip contact STBJa connected in series in the trip circuit is connected, and the anti-trip relay 1TBJUa is started. The normally open contact of 1TBJUa is connected and self-maintaining, and the normally closed contact disconnects the closing circuit, realizing the first set of intelligent terminal anti-trip function.


However, when the second set of intelligent terminals trips, because the circuit breaker closing circuit is connected to the first set of intelligent terminals, and the second set of tripping circuits are independent from the first set of intelligent terminals, the anti-trip relay 1TBJUa of the closing circuit will not be activated, and its anti-trip function will not be realized.