Converter valve high-voltage operation circuit, field test system and control method

Abstract

The invention provides a converter valve high-voltage operation circuit, a field test system and a control method. The operation circuit comprises two current conversion chains and one or two cascaded energy supply chains, wherein the two current conversion chains respectively comprise N sub-modules and M sub-modules; each cascaded energy supply chain comprises at least N-1 or at least M-1 diode units; each sub-module comprises a direct-current capacitor and a power unit which are connected in parallel; AC ends of the sub-modules are connected in series, AC ends of the head sub-module and the tail sub-module are led out to serve as AC ends of commutation chains, one AC ends of the two commutation chains are connected through a connecting reactor, and the other AC ends are in short circuit; and the diode units are connected in series in the same direction, the cathode end of the cascaded energy supply chain is connected with the anode of the direct-current capacitor of the tail sub-module, and the anode ends of all the diode units are in one-to-one correspondence with the anode of the direct-current capacitor of the sub-module of the corresponding current conversion chain or are connected through a first current limiter.

Description

technical field [0001] The application relates to the technical field of high-power electric power electronic conversion, in particular to a high-voltage operating circuit of a converter valve, a field test system and a control method. Background technique [0002] With the application and development of power electronic technology in power systems, power electronic equipment is developing towards high-voltage and large-capacity modularization, especially in flexible direct current transmission systems and chained static var generators. It consists of sub-modules connected in series or parallel. [0003] Taking offshore wind power flexible direct system as an example, offshore wind power grid connection is an important application of flexible direct current transmission, and flexible direct offshore converter stations need to be built on offshore platforms. Considering the limitation of offshore construction conditions, it is impossible to complete the installation and test...

AI Technical Summary

Problems solved by technology

The existing test technology needs to use high voltage to test the converter chain, such as the patent "CN107561456A, a power module test device and test method". The capacity of the low-voltage power supply to complete the experiment

The patent "CN111026082 A A test circuit and test method for a converter chain and its valve base controller" also provides a test circuit and test method for a converter chain, which uses a low-voltage output auxiliary converter valve and connected reactance The converter constructs a constant current source, and uses the low-voltage constant current source to supply energy to the measured converter valve. Since the auxiliary converter valve is limited by the output voltage of the DC auxiliary power supply, it cannot output high voltage through cascading. Therefore, during the charging and testing process , the two ends of the converter valve to be tested cannot withstand high voltage, most of the converter valve sub-modules are in a bypass state, and few quantum modules are put into the circuit in turn, which is essentially a low-voltage test system with low test efficiency and Unable to verify the working condition of high voltage and high power operation

[0005] On the other hand, taking the flexible HVDC project as an example, it is usually necessary to assemble the sub-modules into valve towers during the construction process, and then test the converter valves, which greatly limits the flexibility of the test. The existing test scheme can only carry out sub-system tests such as sub-module function test or insulation test; due to the lack of a high-voltage and high-power operation test scheme for the entire converter chain, the test items are incomplete and the test efficiency is low

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