Interval overvoltage online monitoring device for electric power system and method thereof

Abstract

The present invention provides an internal overvoltage online monitoring device for an electric power system and a method thereof, which can monitor the internal overvoltage of each voltage class. Thedevice uses monitoring apparatuses for collecting synchronously and at high speed, automatically recording, storing, displaying transient electric quantity, and the like, can monitor the transient and stable electric quantities of the power system. The number of synchronous collecting channels of the device can reach up to 16, and the synchronous collecting frequency can reach 100 kHz. The methodcomprises circularly collecting 100mS data according to the set parameters, recording the data for 4.8 s if any channel accords with the starting condition, and storing the recorded data to the hardware. The device can calculate transient harmonics (up to 50 orders) of any part of data wave, give the total harmonic distortion, each harmonic ratio and each harmonic value. The device has computer network function, therefore remote control, data transmission, and offline data analysis, time calculation, waveform amplification and harmonic calculation of the device can be carried out via computernetwork.

Description

technical field [0001] The invention relates to an on-line monitoring device and method for internal overvoltage of a power system, in particular to an internal overvoltage on-line monitoring device and method suitable for various voltage levels of 10kV to 1000kV. technical background [0002] The reliability of high-voltage power system operation depends to a large extent on the working condition of the insulation. It is of great significance to correctly specify the insulation level of the system. The overvoltage plays a decisive role in the selection of the system insulation level. Internal overvoltage is the voltage increase caused by the oscillation conversion or transmission of electromagnetic energy in the system caused by the change of system parameters due to circuit breaker operation, failure or other reasons in the power system. This change may cause damage to the system. harm. With the increase of transmission voltage level and the increase of long-distance tra...

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Problems solved by technology

[0003] At present, the main deficiency of the existing overvoltage online monitoring device is the pursuit of comprehensive overvoltage monitoring, but because the frequency of the external overvoltage, which accounts for less than 10%, reaches about 1MHz, and the wave head of lightning reaches 1.2 microseconds, this requires the acquisition frequency It should reach 60MHz, and the main frequency of the internal overvoltage phenomenon, which accounts for 90%, is concentrated at 3kHz. At the same time, due to the requirement of system reclosing, the time should exceed 4 seconds

This makes other current overvoltage on-line monitoring devices usually have only 4 channels, the acquisition speed is 20MHz, and the time does not exceed 500 milliseconds, so it is basically impossible to test a large number of internal overvoltage processes that last for a long time. voltage divider, so it cannot be installed at voltage levels above 10kV

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