220 thousand volt high-voltage t-connection line three-side longitudinal protection device

Abstract

The invention is a 220KV high-voltage 'T'-connected three-side vertically-connected protector, including: a system power C-side transformer substation, a load A-side transformer substation and a load B-side transformer substation, where the C-side transformer substation is provided with a first signal transceiver and a second one, the A-side transformer is provided with a signal transceiver and the B-side transformer is provided with a signal transceiver, too, and two pairs of signal transceiver composed of them have a different communication frequency. The margins of the first and second signal transceivers can be adjusted independently, and the test of two channels can be made, respectively, which can not cover the conditions of channel abnormality.

Description

technical field [0001] The invention relates to a protection device in a high-voltage power grid system. Background technique [0002] In the prior art, "T" connection line is used as a wiring method, which saves investment and shortens the construction period. It has been widely used in low-voltage power grid systems. However, in high-voltage power grids, it is required to quickly remove the entire line for line faults. The setting of the fixed value is difficult, so it is rarely used, so it is clearly stipulated in GB14285 "Technical Regulations for Relay Protection and Safety Automatic Devices" that "it is not suitable to connect branch lines or branch transformers to the tie line of the power grid". However, in recent years, due to the strengthening of 500KV grids in some areas, more terminal substations have appeared in 220KV power grids. In order to improve the utilization rate of 220KV lines and avoid the complexity of protection setting calc...

AI Technical Summary

Problems solved by technology

With the emergence of "T" connection lines, three-terminal longitudinal protection has begun to attract people's attention. In foreign countries, it is common to use fiber optic channels to realize three-terminal split-phase current differential protection. At present, there are relatively mature products, but as a communication Fiber Channel is expensive and generally applicable to new lines, so the prospect of promotion is not good

When using single-frequency single-channel mode for communication, it is difficult for the receiving margin between the three terminals to meet the technical indicators at the same time. The reason is that the communication distance between the three terminals is different, resulting in different attenuation. For daily channel detection, it is difficult to find channel defects.

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