Differential protection signal synchronizing method for distribution network system

Abstract

The invention relates to a differential protection signal synchronizing method for a distribution network system. A distribution network automatic device is arranged in each distribution network place in the distribution network system; each distribution network automatic device comprises a terminal device or a protection device; each distribution network automatic device is provided with a differential protection part; each distribution network automatic device calculates system current and voltage vectors with stable phase angles, which are sampled by the distribution network automatic device, by adopting a Fourier recursive algorithm and the system current and voltage vectors are transmitted to the adjacent distribution network automatic device by data links through the distribution network system; and on the basis of the basically consistent voltage vectors at each point in the distribution network system, each distribution network automatic device corrects the current vector of the adjacent distribution network automatic device according to the deviation of a reference voltage vector of the adjacent distribution network automatic device so as to implement the synchronization of the current vector on each side of the differential protection part of each distribution network automatic device. The differential protection signal synchronizing method is applied to the distribution network system; the differential protection on two sides or a plurality of sides is flexibly implemented; the synchronizing method is simple to implement, does not need a special point-to-point data link, has low data exchange capacity between the protection parts and has low requirement on the real-time performance of the data transmission, low calculated quantity and high synchronizing accuracy.

Description

technical field [0001] The invention relates to a synchronization method, in particular to a distribution network system differential protection signal synchronization method and a protection device using the method. Background technique [0002] With the development of various technologies of the smart grid, the reliability requirements for the distribution network power supply of the power grid are also increasing day by day. The original distribution network protection adopts simple overcurrent and time step-by-step coordination methods, which can no longer meet the needs of quick action and selectivity. At the same time, with the access of distributed power, the original protection configuration and setting principles can no longer meet the requirements of operation. On the other hand, after the distribution network fault cuts off the power supply, the requirements for backup power supply recovery and power supply stability control after recovery are also increasing. To...

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Problems solved by technology

However, differential protection also has technical difficulties in synchronous sampling. Due to the uncertainty of channel data transmission delay in the above-mentioned communication network, the traditional "ping-pong" synchronous sampling principle of differential protection cannot be applied

At the same time, GPS and other satellite clock synchronization is not suitable for application and promotion in relay protection configuration due to reliability reasons.

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