Digital optical fiber differential protection method based on current state variables

A current state and differential protection technology, which is applied in the direction of automatic disconnection emergency protection devices, emergency protection circuit devices, electrical components, etc., can solve the problem of consistent transmission characteristics of current transformers and optical fiber differential of current transformer transmission characteristics Protection device misoperation and other problems, to achieve the effect of simple criteria

CN104218545AActive Publication Date: 2014-12-17北京天能继保电力科技有限公司
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2014-12-17

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Abstract

The invention provides a digital optical fiber differential protection method based on current state variables. The digital optical fiber differential protection method comprises determining a protection action by use of a split-phase differential criterion according to the current state variables on the two sides of a line. According to the digital optical fiber differential protection method, the differential protection action criterion requires the current state variables on the two sides for calculating differential current and braking current instead of synchronously sampled data on the two sides and does not require the consistence of the characteristics of transformers on the two sides; the digital optical fiber differential protection method based on the current state variables is suitable for various conventional current transformers or electronic current transformers.
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Description

technical field

[0001] The invention relates to a method in the technical field of electric power system relay protection, in particular to a digital optical fiber differential protection method based on current state quantities. Background technique

[0002] The principle of current differential protection is the most ideal relay protection principle. Optical fiber differential protection for transmission lines has become one of the mainstream configurations for power system line protection. At present, the digital optical fiber differential protection is to convert the current signal at both ends of the transmission line into a digital signal and transmit it to the opposite end through the optical fiber. The digital signal transmitted is the sampled value of the terminal current or the real and imaginary parts of the current phasor. The protection device receives the digital signal from the opposite end and then forms a differential protection with the digital signal at ...

Examples

Embodiment Construction

[0041] The specific embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0042] Such as figure 1 as shown, figure 1 It is a flow chart of the method of the present invention. The present invention provides a digital optical fiber differential protection method based on current state quantities. The method uses phase-separated differential criteria to judge the protection action behavior according to the current state quantities on both sides of the line. Specifically include the following steps:

[0043] Step 1. Determine the secondary effective value and current direction of the current on one side of the line.

[0044] Step 2. Determine whether the system is a double-side power supply system or a single-side power supply system. When the system is a double-side power supply system, determine the current state quantity according to the method for determining the current state quantity of the double-s...