Electric energy metering method and device suitable for three-half wiring of intelligent substation

Abstract

The invention relates to an electric energy metering method suitable for three-half wiring of an intelligent substation. The method comprises: acquiring bus voltage, middle switching current and sideswitching current at a high speed according to a sampling interval divided by a three-half wiring mode, and directly transmitting the bus voltage, the middle switching current and the side switching current to a digital electric energy meter in a point-to-point manner by a merging unit in the interval; forwarding through a physical layer of the optical fiber sending port; judging the synchronization state of the merging unit, and selecting a proper synchronization method for synchronous sampling; then, calculating a line current sampling sum value, and obtaining the electric quantity of three-half wiring by combining bus voltage sampling; and finally, outputting electric quantity information through the MMS message. The invention further discloses an electric energy metering device suitable for three-half wiring of the intelligent substation. According to the invention, the influence of the stability of sampling value networking transmission on the three-half wiring electric quantity metering precision is avoided, the dependence of multi-interval metering on a whole station clock synchronization system is reduced, the synchronous fault-tolerant capability of the digital electric energy meter is improved, and the reliability of overall electric energy metering is improved.

Description

technical field [0001] The invention relates to the technical field of smart substation metering in electric power systems, in particular to an electric energy metering method and device suitable for three-half wiring of smart substations. Background technique [0002] Smart substations use digital methods to transmit electrical sampling information, which effectively curbs the repeated configuration of acquisition equipment, improves the flexibility of information transmission in substations, and enhances the data interaction and processing capabilities of substations, but at the same time makes the information relationship and function identification of substations complicated. To a certain extent, it increases the difficulty of implementing on-site work in substations. [0003] The three-half connection is composed of three circuit breakers connected in series between the busbars and two outgoing lines. It has high power supply reliability and operation flexibility, and i...

AI Technical Summary

Problems solved by technology

The sampling value network is implemented based on network switches. When the switches work abnormally, data loss points or excessive transmission delays will occur, which will affect the reliability of energy metering.

In particular, the network pressure problem will be introduced after the sampling value network is transmitted. When the network design is unreasonable, the transmission load is heavy, or the network equipment is abnormal, a large number of invalid Ethernet interference messages may be generated in the sampling value network, affecting the switch. The data processing capability even leads to the paralysis of the sampling value network, and the electric energy cannot be measured

[0006] (2) Heavily dependent on the clock synchronization system of the whole station

The reliability of the clock synchronization source, the communication stability of the synchronization optical fiber, and the accuracy of the synchronization algorithm inside the merging unit may affect the synchronization of the sampled data

When the synchronization system in the station fails, the energy meter cannot reliably obtain the required sampling value, and there are certain defects in the realization principle

[0007] (3) The technical advantages of digital metering in smart substations are not fully utilized

In the current digital electric energy metering system, the connection between the electric energy meter and the station control layer of the substation is mainly realized by the DL / T 645 protocol of the traditional RS485 connection. This communication mode is simple to implement, but the data transmission is slow; Sampling, data conversion will lose accuracy; lack of information optimization for the characteristics of equipment at the process level of smart substations, and cannot accurately reflect the abnormal state of digital sampling value transmission

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