System and method for evaluating status of oscillation circuit of active high-voltage direct-current switch

Abstract

The invention discloses a system and a method for evaluating a status of an oscillation circuit of an active high-voltage direct-current switch, and relates to a technology for evaluating the status of the oscillation circuit of the high-voltage direct-current switch. In the method, the current of the oscillation circuit is acquired by a programmable automation controller (PAC) and a hall current sensor, and the acquired current signal is transmitted to a background personal computer (PC) via a general packet radio service (GPRS) wireless transmission module, so on-line detection on the current of the oscillation circuit of the high-voltage direct-current switch is realized; and the status of the oscillation circuit is evaluated by programming by taking the background PC as a working platform. The method comprises the following steps of: (1) determining the maximum arc time Tm of the oscillation circuit; (2) determining standard arc time Tw of the oscillation circuit; and (3) evaluating the status of the oscillation circuit. By the invention, the status of the oscillation circuit of the direct-current switch can be evaluated at any time; the waveform of the current generated by the oscillation circuit is kept stable; and the long-term reliable operation of a direct-current power transmission system and the safety and stability of the overall system are guaranteed.

Description

technical field [0001] The invention relates to a state evaluation technology of a high-voltage direct current switch oscillation circuit, in particular to an active high-voltage direct current switch oscillation state evaluation system and a method thereof. Background technique [0002] Since the end of the 1980s, the research on DC transmission technology in my country has made rapid progress. At present, there are more than ten ±500kV DC projects in China that have been put into operation. my country plans to put more than 30 DC projects into operation before 2020; at the same time, in order to realize the strategy of "power transmission from west to east", the country is vigorously promoting UHV DC transmission projects including ±400kV, ±660kV, ±800kV and ±1000kV In the future, DC transmission will become an important part of my country's power grid. [0003] The DC switch is one of the important equipment in the converter station of the DC transmission project. Its mai...

AI Technical Summary

Problems solved by technology

[0008] 1. The premise of calculating the inductance L and resistance R according to the test current waveform is that the capacitive reactance value of the capacitor C must be known, and the field test generally uses a multimeter to estimate the capacitance value, which also brings errors to the calculation accuracy

[0009] 2. When building the test circuit, devices such as voltage regulators and rectifiers must be configured. Since the entire DC circuit breaker is installed on an insulating platform, when charging the capacitor C, it is necessary to lead down from both ends of the capacitor C; at the same time In order to connect the resistance shunt meter R in series to the discharge circuit, a wire must be removed from a connection port of the oscillating circuit. The wiring of this test method is relatively cumbersome, and the staff needs to climb up and disconnect the wire on site; what is more serious is that due to The inductance and resistance of the connected wires will seriously affect the validity and accuracy of the calculated inductance and resistance values

[0010] 3. The entire test process must be carried out in an offline state, resulting in the lack of real-time performance of the measured waveform and calculation results, which cannot effectively reflect the breaking process and operating status of the DC circuit breaker, and also affect the reliability of the DC transmission system and energy availability

[0014] 1. These methods are all off-line, and can only be carried out when the converter station is overhauled. These values ​​cannot be known during the normal operation of the converter station. Once some of the parameters occur due to equipment aging or overvoltage shock When it changes, it is impossible to know the specific value of the change

[0015] 2. There are many separate components for the DC switch, the test period is very long, and the cost of manpower and material resources is relatively large

[0016] 3. The offline parameter measurement test of the existing DC switch needs to untie the connecting line of the DC switch oscillation circuit

[0017] 4. The offline parameter measurement test of the existing DC switch needs to add a very long extension line to pass the shunt meter into the DC switch oscillation circuit

Secondly, the resistance parameter is calculated according to the inductance L parameter and the envelope of the oscillating current, which is not completely consistent with the actual situation on site.

[0019] 6. Since the R, L, and C parameters of the oscillation circuit calculated according to the above method are inaccurate, the evaluation status obtained is also inaccurate

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