LCC fault blocking voltage control method in hybrid double-infeed DC system
A DC system and blocking voltage technology, applied in the field of power transmission and distribution, can solve problems such as system reactive power surplus, converter equipment damage, AC bus voltage rise, etc., and achieve the effect of suppressing transient overvoltage and suppressing phenomena
Active Publication Date: 2019-09-03
ELECTRIC POWER RES INST OF STATE GRID ZHEJIANG ELECTRIC POWER COMAPNY +1
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There are two types of converters currently in use, one is the voltage source converter (Voltage Source Converter, VSC), the other is the grid commutated converter (Line Commutated Converter, LCC), the grid commutated converter HVDC (line commutated converter based high voltage direct current, LCC-HVDC) is currently the most widely used form of HVDC transmission system. Under the fault blocking condition of the HVDC system, due to the existence of the LCC reactive power compensation device, the reactive power of the system will be excessive, the AC bus voltage will rise, and a transient overvoltage will be formed, which will cause damage to the converter equipment. Generally, additional configuration is required Device suppresses transient overvoltages caused by LCC fault latching
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[0030] The present invention will be described in detail below in conjunction with the accompanying drawings. A method for controlling LCC fault blocking voltage in a hybrid double-fed DC system proposed by the present invention, firstly detects the fault of the LCC-HVDC system to judge whether the fault blocking occurs in the LCC-HVDC system, if a fault blocking occurs, the VSC-HVDC system outputs Enable signal E n =1, otherwise output enable signal E n =0, then according to the current reference signal i output by the VSC-HVDC system dref0 i qref0 and the enable signal E n to i dref0 i qref0 Perform limit processing.
[0031] Further, the method for judging whether the LCC-HVDC system is fault-locked is to detect the voltage rise rate dV of the AC bus of the LCC-HVDC system through the voltage transformer acm / dt, the detected voltage rise rate dV acm / dt and rising rate limit Vv max For comparison, if dV acm / dt>Vv max , it is determined that a latching fault occ...
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The invention belongs to the technical field of power transmission and distribution, and particularly relates to a method for controlling LCC (Line Commutated Converter) failure locking voltage in a hybrid double-feed-in direct current system. According to the invention, the rising rate of AC bus voltage is firstly detected, then the rising rate is compared with a maximum allowable rising rate threshold of the AC bus voltage so as to judge whether a locking failure occurs in LCC-HVDC (Line Commutated Converter based High Voltage Direct Current) transmission or not, a reference value of inner ring current of a VSC (Voltage Source Converter) is adjusted through a received enable signal, the VSC is enabled to reduce active power outputted by VSC-HVDC through appropriately reducing the d-axis reference current amplitude when a locking failure occurs in LCC-HVDC, and a q-axis current reference value is improved so as to enhance the supporting capacity of VSC-HVDC for the AC bus voltage. According to the reactive voltage emergency control method provided by the invention, a phenomenon of transient overvoltage in the hybrid double-feed-in direct current system when a locking failure occurs in LCC-HVDC can be effectively improved.
Description
technical field [0001] The invention belongs to the technical field of power transmission and distribution, and in particular relates to a method for controlling LCC fault blocking voltage in a hybrid double-feed direct current system. Background technique [0002] With the development of society and economy, the demand for electricity continues to increase, and the development of power electronics technology provides new options for the transmission of electric energy. High Voltage Direct Current Transmission (HVDC for short) has gradually matured after decades of development. It is mainly used in long-distance large-capacity power transmission, asynchronous networking of AC systems, light DC power transmission, solar energy, wind energy, photovoltaics, etc. New energy transmission. There are two types of converters currently in use, one is the voltage source converter (Voltage Source Converter, VSC), the other is the grid commutated converter (Line Commutated Converter, L...
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IPC IPC(8): H02J3/36H02J3/18H02J3/16
CPCH02J3/16H02J3/18H02J3/36Y02E40/30Y02E60/60
Inventor 陆翌童凯郭春义赵成勇刘炜
Owner ELECTRIC POWER RES INST OF STATE GRID ZHEJIANG ELECTRIC POWER COMAPNY