AC-DC large power grid transient voltage stability evaluation method and system

Abstract

The invention discloses an AC / DC large power grid transient voltage stability evaluation method and system. The method comprises the following steps of constructing a training sample set based on thehistorical power flow data; taking an expected output vector of the training sample set as a transient voltage stability index; constructing a converter bus transient voltage stability rapid evaluation model based on the transient voltage stability index; training the converter bus transient voltage stability rapid evaluation model by using the training sample set; and identifying a high-risk operation scene influencing the AC / DC large power grid transient voltage stability on line by using the trained converter bus transient voltage stability rapid evaluation model. According to the method, the minimum value of the secondary drop of the converter bus voltage after the fault is used as the output, the converter bus transient voltage stability rapid evaluation model is established, and theload active and reactive power, the generator active and reactive output and the key power transmission line power flow data obtained by rolling are input into the model to evaluate the stability ofthe power grid transient voltage in real time.

Description

technical field [0001] The invention relates to a transient voltage stability evaluation method and system of an AC / DC large power grid, and belongs to the technical field of power system voltage stability evaluation technology. Background technique [0002] With the intensive operation of UHVDC projects and the changes in load composition and characteristics, the proportion of power electronic components is increasing day by day, the voltage stability problem of large AC and DC power grids is prominent, and the risk of major blackouts is intensified. The normal operation of the high-voltage DC system requires sufficient reactive power support from the AC system. A partial short-circuit fault in the AC system may cause transient voltage instability in the DC receiving end system, causing continuous commutation failure or lockout in HVDC (High Voltage Direct Current Transmission) , destroying the security and stability of the entire system. After a large disturbance occurs i...

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Problems solved by technology

[0004] The inventors have found that the existing transient voltage stability evaluation methods have at least the following deficiencies: (1) The HVDC transmission system accounts for an increasing proportion of the transmission network, and the DC system is connected to the AC system through a converter. Commutation failure or DC blocking will cause power impact on the AC system, and the failure of the AC system will cause voltage fluctuations in the commutation bus, affecting the normal operation of the DC system. However, the existing transient voltage stability evaluation methods do not fully consider the DC system and the AC system. mutual influence

(2) With the expansion of the grid scale, the calculation time of the existing methods is long, and it is difficult to apply and evaluate online in real time

(3) The evaluation accuracy of traditional shallow neural network is low, and it cannot be applied to large-scale power grids

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