Portable PT voltage mirror image source device

Abstract

The invention provides a portable PT voltage mirror image source device. The portable PT voltage mirror image source device comprises a plurality of voltage sampling devices and a standard voltage source device. The voltage sampling devices are installed in a PT voltage cabinet in a transformer substation, and are used for obtaining a field bus PT reference voltage signal and sending PT voltage frequency phase information in a wireless continuous pulse synchronization mode. The standard voltage source device continuously receives a pulse synchronization signal in real time to obtain frequency and phase information of the PT voltage signal. Under the control of a control module, a phase locking module in the standard voltage source device outputs a reference voltage signal of program control amplitude modulation and phase modulation through an internal digital-to-analog conversion unit, and a power amplifier amplifies the reference voltage signal and outputs a mirror image PT voltage signal with the same frequency and the same phase as the PT reference voltage signal. The voltage source device is powered by an internal battery, and is small in size, light in weight and convenient to operate on site. By using the PT voltage mirror image source, the short circuit risk caused by PT voltage sampling can be avoided, the manpower for taking PT voltage signals is saved, and the efficiency of on-site live testing is improved.

Description

technical field [0001] The invention relates to the live test field of electric equipment, in particular to a portable PT voltage mirror source device. Background technique [0002] Zinc oxide arrester is a protective device for primary equipment. According to operating experience, its leakage current and resistive current are in the microampere level. When the increase exceeds 50%, the arrester needs to be overhauled. The live test of the arrester is the main means of its condition maintenance. By measuring the resistive current and leakage current of the arrester and comparing it with the test data of the same period of the previous year, it can assist in judging the operating state of the arrester. The commonly used live test method is based on the PT voltage vector projection method. The resistive current is obtained by synchronously collecting the PT voltage signal and the leakage current signal of the arrester, and calculating through the angle projection. [0003] In...

AI Technical Summary

Problems solved by technology

[0003] In order to obtain the PT voltage reference, live testers need to open the PT cabinet to connect to the voltage sampling signal line on site. Due to the large number of terminal blocks in the PT cabinet, there may be wrong connection of the terminal blocks, which may cause test data errors and affect test efficiency; at the same time, it may cause damage during the wiring process The secondary side of the PT voltage is short-circuited, resulting in malfunction of the relay

In order to avoid the risk of connecting to the PT signal, there is currently a resistive current test using the power supply and the induced voltage as a reference, but the measurement results have large errors and cannot truly reflect the state of the arrester

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