CN103248005B - A kind of analyses for double circuits on same tower AC electric quantity sampling synchronization method - Google Patents

Abstract

The invention discloses a synchronization method for sampling and synchronizing AC electrical quantities of double-circuit lines paralleled on the same pole. The method of the present invention firstly measures the fault reverse positive sequence current at terminal m of the parallel double circuit line on the same pole Reverse positive sequence current opposite to n-terminal fault calculate take the lead The angle θ; and then select the transmission to the m-terminal substation protection device The AC electrical quantity at the n-terminal of the parallel double-circuit line on the same pole at the sampling time and the AC electrical quantity at the m-terminal of the parallel double-circuit line on the same pole at the sampling time t collected by the substation protection device at the m-terminal are synchronous data for relay protection calculation; Among them, φ=phases A, B, and C of circuit I, and phases A, B, and C of circuit II; N is the number of sampling points in a fundamental frequency cycle; △t is the sampling interval; t is the sampling time. The method of the invention realizes that the double-terminal AC electric quantity sampling synchronization error of parallel double-circuit lines on the same pole is zero, the algorithm principle is simple, and the calculation amount added to computer processing is small, and the relay protection of double-circuit lines parallel on the same pole is not affected. Action speed, strong practicability.

Description

A Synchronization Method for Sampling AC Electric Quantities of Double-Circuit Lines Parallel on the Same Rod

technical field

The invention relates to the technical field of electric power system relay protection, in particular to a method for sampling and synchronizing AC electrical quantities of double-circuit lines paralleled on the same pole.

Background technique

Due to the randomness and dispersion of the CPU's response time to the interrupt proposed by the hardware synchronization link, there is an error in the sampling synchronization accuracy, which is an inherent defect of the hardware synchronization sampling method. The AC sampling synchronization methods used in relay protection are mainly divided into two categories. One is to reduce the measurement error by processing the sampling data or correcting the measurement results when the synchronization error is constant; the second is to reduce the measurement error by Reducing the synchronization error reduces the measurement error. The first type of method has poor practicability due to the complex processing process, large amount of calculation and long time-consuming data processing. The second type of method ignores the impact of uneven sampling time intervals on measurement results, resulting in errors in sampling synchronization.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art, and provide a method for sampling and synchronizing the AC electrical quantity of parallel double-circuit lines on the same pole.

For accomplishing above-mentioned object, the present invention adopts following technical scheme:

A method for sampling and synchronizing AC electrical quantities of double-circuit lines paralleled on the same pole, the gist of which is to include the following steps:

(1) Provide m-terminal substation protection device and n-terminal substation protection device respectively installed in the m-terminal substation of parallel double-circuit line on the same pole and the n-terminal substation of parallel double-circuit line on the same pole;

(2) The m-terminal substation protection device collects the AC electrical quantity at the m-end of the parallel double-circuit line on the same pole; The AC electrical quantity at the n-terminal is transmitted to the protection device of the m-terminal substation through optical fiber communication; among them, m and n are respectively the names of the substations at both ends connected by the double-circuit line on the same pole;

(3) The protection device of the m-terminal substation uses the Fourier algorithm and the six-sequence component method to calculate the reverse positive-sequence current of the reverse fault at the m-terminal of the parallel double-circuit line on the same pole Among them, φ=phases A, B, and C of circuit I, and phases A, B, and C of circuit II;

The protection device of the m-terminal substation uses the Fourier algorithm and the six-sequence component method to calculate the reverse positive-sequence current in the opposite direction of the fault at the n-terminal of the parallel double-circuit line on the same pole Among them, φ=phases A, B, and C of circuit I, and phases A, B, and C of circuit II;

(4) Calculation of protection device of m-terminal substation take the lead Angle

(5) The m-terminal substation protection device is selected to transmit to the m-terminal substation protection device The AC electrical quantity at the n-terminal of the parallel double-circuit line on the same pole at the sampling time and the AC electrical quantity at the m-terminal of the parallel double-circuit line on the same pole at the sampling time t collected by the substation protection device at the m-terminal are synchronous data for relay protection calculation; Among them, N is the number of sampling points of a fundamental frequency period; △t is the sampling interval; t is the sampling time.

Features and technical achievements of the present invention:

The method of the present invention realizes that the double-terminal AC electric quantity sampling synchronization error of the double-circuit line paralleled on the same pole is zero, the principle is simple, the calculation amount added to the computer processing is small, and the action of relay protection of the double-circuit line paralleled on the same pole is not affected. Speed and practicality.

Description of drawings

Fig. 1 is a schematic diagram of a double-circuit line power transmission system on the same pole parallel to the rack applying the present invention.

detailed description

The technical solution of the present invention will be further described in detail according to the accompanying drawings.

Fig. 1 is a schematic diagram of a double-circuit line power transmission system on the same pole parallel to the rack applying the present invention. The protection devices in this embodiment are respectively installed in the m-terminal substation and the n-terminal substation of the parallel double-circuit line on the same pole. The protection device of the m-terminal substation collects the AC electrical quantity of the m-terminal of the parallel double-circuit line on the same pole. The n-terminal substation protection device collects the AC electrical quantity at the n-terminal of the parallel double-circuit line on the same pole, and transmits the AC electrical quantity at the n-terminal of the parallel double-circuit line on the same pole to the m-terminal substation protection device through optical fiber communication; where m and n are respectively It is the name of the substation at both ends connected by the parallel double-circuit line on the same pole.

The m-terminal substation protection device uses the Fourier algorithm and the six-sequence component method to calculate the fault reverse positive sequence current at the m-terminal of the parallel double-circuit line on the same pole Among them, φ=phases A, B, and C of circuit I, phase A, B, and C of circuit II; the six-sequence component can be divided into two types: forward component and reverse component, and F represents the reverse component of the six-sequence component. To the component.

The protection device of the m-terminal substation uses the Fourier algorithm and the six-sequence component method to calculate the reverse positive-sequence current in the opposite direction of the fault at the n-terminal of the parallel double-circuit line on the same pole Among them, φ=phases A, B, and C of circuit I, phase A, B, and C of circuit II; the six-sequence component can be divided into two types: forward component and reverse component, and F represents the reverse component of the six-sequence component. To the component.

Calculation of Protective Devices in M-terminal Substation take the lead Angle

The m-terminal substation protection device selects the transmission to the m-terminal substation protection device The AC electrical quantity at the n-terminal of the parallel double-circuit line on the same pole at the sampling time and the AC electrical quantity at the m-terminal of the parallel double-circuit line on the same pole at the sampling time t collected by the substation protection device at the m-terminal are synchronous data for relay protection calculation; Among them, N is the number of sampling points of a fundamental frequency period; △t is the sampling interval; t is the sampling time.

The above descriptions are only preferred specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto, any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention , should be covered within the protection scope of the present invention.

Claims (1)

1. A method for sampling and synchronizing the AC electrical quantities of double-circuit lines with parallel racks on the same pole, is characterized in that it comprises the following steps: (1) Provide m-terminal substation protection device and n-terminal substation protection device respectively installed in the m-terminal substation of parallel double-circuit line on the same pole and the n-terminal substation of parallel double-circuit line on the same pole; (2) The m-terminal substation protection device collects the AC electrical quantity at the m-end of the parallel double-circuit line on the same pole; The AC electrical quantity at the n-terminal is transmitted to the protection device of the m-terminal substation through optical fiber communication; among them, m and n are respectively the names of the substations at both ends connected by the double-circuit line on the same pole; (3) The protection device of the m-terminal substation uses the Fourier algorithm and the six-sequence component method to calculate the reverse positive-sequence current of the reverse fault at the m-terminal of the parallel double-circuit line on the same pole Among them, φ=phases A, B, and C of circuit I, and phases A, B, and C of circuit II; The protection device of the m-terminal substation uses the Fourier algorithm and the six-sequence component method to calculate the reverse positive-sequence current in the opposite direction of the fault at the n-terminal of the parallel double-circuit line on the same pole Among them, φ=phases A, B, and C of circuit I, and phases A, B, and C of circuit II; The AC electrical quantity at the n-terminal of the parallel double-circuit line and the AC electrical quantity at the m-terminal of the parallel double-circuit line collected by the protection device of the m-terminal substation at the sampling time t are synchronous data used for relay protection calculations; where N is a The number of sampling points in the fundamental frequency period; △t is the sampling interval; t is the sampling time.