Low voltage load test method and device

Abstract

The invention provides a low-voltage load test method and device. The method comprises the following steps of selecting an instation power supply as a benchmark, powering a single-phase riser instrument and a single-phase voltage regulator by utilizing the power supply, primarily increasing the current of a CT of a device to be tested by utilizing the single-phase riser instrument, and secondarily boosting the voltage of a PT of the device to be tested by utilizing the single-phase voltage regulator; acquiring the phase of the input current and the output current of the single-phase riser instrument, calculating the phase difference, and judging whether the phase difference stays within the predetermined range; acquiring the phase of the input voltage and the phase of the output voltage of the single-phase voltage regulator if the phase difference stays in the predetermined range, calculating the phase difference, and judging the phase differences stays in a predetermined range; switching the voltage to a relay if the phase difference of the input voltage and the output voltage stays in the predetermined range, calculating the phase difference between the voltage and the current of the phase of the device to be tested, and determining whether the polarity of a current loop and a voltage loop is correct or not according to the phase difference. The test method is flexible, convenient, strong in practicability, high in working efficiency and capable of guaranteeing the safety of the system.

Description

technical field [0001] The invention relates to the field of power systems, in particular to a low-voltage load testing method and a low-voltage load testing device. Background technique [0002] Newly built or rebuilt power transmission equipment (such as transmission lines, transformers, etc.) must meet the requirements of relay protection, measurement and monitoring, metering and billing, and power transmission before power is transmitted to users. It is necessary to conduct a load test to determine whether the polarity of the current loop and voltage loop of the power transmission equipment is correct. [0003] The traditional load test method is: by using a large system with a primary device to directly charge the device with actual current to perform a load test. That is, the traditional load test method is to check the correctness of the secondary current loop and voltage loop, that is, the secondary loop of CT (current transformer, current transformer) and PT (poten...

AI Technical Summary

Problems solved by technology

[0005] In addition, the traditional load test method itself has certain risks. It is not known whether the polarity is correct before the load is applied, and various complicated safety measures need to be taken (such as: exiting the busbar protection due to uncertain polarity, automatic switching of the backup power supply, safety and stability system, line or main transformer differential protection, protection related to power direction, etc.), these safety measures themselves bring great risks to the system

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