Fuzzy control-based continuous commutation failure prevention control method for high-voltage direct-current transmission system

Abstract

The invention relates to a fuzzy control-based continuous commutation failure prevention control method for a high-voltage direct-current transmission system. The method comprises the steps of creating a fuzzy control output result lookup table; collecting a valve side commutation voltage of an inverter side converter transformer, and calculating a sudden change quantity delta of a phase intervalof adjacent commutation voltages; judging whether an advance trigger angle tracking controller is started or not according to a hysteresis comparator; after the advance trigger angle tracking controller is started, collecting an advance trigger angle beta and an instruction beta inv of the advance trigger angle beta, and calculating a difference value e between an actually measured value and the instruction, and a change quantity delta e of two adjacent difference values; transmitting input variables e and delta e which belong to a physical theory domain to a fuzzy controller, converting the input variables into input variables E and DE of a fuzzy theory domain after the input variables are subjected to discretization processing, then querying the lookup table of the fuzzy controller, selecting a corresponding output result, and obtaining a feedforward compensation angle beta cps; and obtaining a compensated advance trigger angle instruction.

Description

technical field [0001] The invention relates to the field of high-voltage direct current transmission control and protection in electric power systems, in particular to a method for preventing and controlling continuous commutation failure of high-voltage direct current transmission based on fuzzy control theory. Background technique [0002] The reverse distribution of my country's power generation resources and electricity demand requires the power system to realize cross-regional, long-distance and large-scale power transmission, and send southwest hydropower, northwest thermal power, and wind power to load centers in North China, Central China, East China, and South China to promote "West Power East East". power transmission" and "northern-south power transmission" power transmission pattern. High voltage direct current (HVDC) transmission has been widely used in long-distance power transmission and power system interconnection due to its advantages of large transmission ...

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Problems solved by technology

"A Virtual Resistor Current Limiting Control Method for Suppressing Continuous Commutation Failure of Traditional DC Transmission" proposes to add a virtual resistor module in the DC control to limit the rapid increase of the DC current in the system recovery stage after the commutation failure, but the virtual resistor module does not affect the DC current. The control introduces harmonic components, resulting in poor control effect

"A Control Method for Suppressing Continuous Commutation Failure of DC Transmission" aims at the problem of severe fluctuations in the starting voltage of the low-voltage current-limiting link after a fault, and uses the DC steady-state characteristic equation to calculate the starting voltage in real time, which eases the change in the starting voltage. To a certain extent, it is beneficial for DC to avoid continuous commutation failure and recover quickly, but the method is less effective in suppressing continuous commutation failure in serious faults

"Continuous Commutation Failure Suppression Strategy of HVDC System Based on Virtual Commutation Area Insufficiency" considered the impact of changes in DC current and commutation voltage on the commutation area, and proposed a lack of virtual commutation area index, and used this to control the DC current command limit, but can only suppress DC continuous commutation failures after minor faults

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