Method for judging disappearance of secondary direct-current power supply of far-end transformer substation

Abstract

The invention discloses a method for judging disappearance of a secondary direct-current power supply of a far-end transformer substation. A power loss alarm contact of the secondary direct-current power supply of the transformer substation is introduced into I / O on-off input of a communication cell measuring and controlling device. The communication bandwidth of MSTP equipment is divided into the protection bandwidth and measuring and controlling bandwidth which are independent from each other, the protection bandwidth is used for conveying protection information, and the measuring and controlling bandwidth is used for conveying access power loss on-off input information of measuring and controlling equipment. A receiving end transformer substation protection device can detect received offside information in real time. The judgment whether a secondary direct-current power supply of an offside transformer substation disappears can be given out in real time by comparing information of the protection bandwidth with information of the measuring and controlling bandwidth. According to the method, a measuring and controlling loop of an independent power supply and a communication loop of independent bandwidth can be utilized to transmit disappearance information of the secondary direct-current power supply. Disappearance of the secondary direct-current power supply of the far-end transformer substation can be accurately recognized in an online mode by comparing the protection bandwidth with the measuring and controlling bandwidth. Thus, decision basis can be provided for following protection strategies or control strategies.

Description

technical field [0001] The invention relates to a method for judging the disappearance of a secondary DC power supply of a remote substation in a power system. Background technique [0002] The disappearance of the secondary DC power supply of the power substation (the DC loss of the protection device or the DC loss of the operating power supply) is a serious accident in the operation of the substation. After the secondary DC power supply disappears, all the protection devices or operating circuits of the substation cannot work. The main transformer, bus differential, high reactance, and line outlets all lose protection. Once a fault occurs, the station will have no protection action, and must wait for the delay action of remote backup protection of other adjacent stations to isolate the fault. Such as figure 1 In station C, the whole station loses power. When f1 fault occurs on the AC line, the line protection of CB2 cannot operate to remove the fault due to the loss of pr...

AI Technical Summary

Problems solved by technology

Since the remote backup protection needs to consider the coordination relationship between segments, its action time is relatively slow. In severe cases, its action time may not meet the requirements of system stability, which poses a serious threat to the safe and stable operation of the system.

If the disappearance of the secondary DC power supply of the substation can be identified online, corresponding strategies can be adopted to speed up the action speed of the adjacent substation protection and quickly remove the fault, but so far, there is no method for online identification of the disappearance of the secondary DC power supply of the substation

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