Method for evaluating electric power system risk based on fault pre-scanning

Abstract

The invention discloses a method for evaluating the electric power system risk based on fault pre-scanning. The method comprises the steps that firstly, according to the current structure of an electric power system and a planning scheme, a corresponding planning scheme model is established; secondly, based on device data and a power grid structure, predicted faults and the possibility of the predicated faults of a power grid are analyzed, and then a pre-scanning fault set is formed; thirdly, through the risk state based on direct-current power flow, screening and ordering are conducted on the predicated fault set, so that a fault state list is formed; fourthly, all power flow corresponding to the faults in the list is worked out, and for the fault with the power flow out of range, the consequence of the fault is load loss; fifthly, according to the load loss of the fault states and the possibility of the fault states, the system risk indicator is worked out; sixthly, according to the system risk indicator, the system weak link is found out. By the adoption of the method for the evaluating electric power system risk based on fault pre-scanning, analysis of all the fault sates in the fault set through alternating-current power flow is avoided, so that the calculation amount of follow-up alternating-current power flow analysis and risk indicator processing is greatly reduced, and a large mount of calculation time is saved.

Description

technical field [0001] The invention belongs to the field of power grid planning and relates to the field of power system risk assessment. Background technique [0002] Large-scale power system fault pre-scanning is more complicated. Its purpose is to calculate the line power flow and bus voltage after one or more components fail to identify whether it causes problems such as line overload, voltage limit, bus isolation or system separation into islands. The core content of the power system risk assessment model is the analysis and calculation of the system state. After a certain system state is obtained by analytical method or simulation method, the state needs to be evaluated and analyzed. In system state assessment, both AC power flow and DC power flow can be used to analyze the risk state of the system. [0003] Although the actual response process of the system, the voltage quality and the actual constraints of the power flow can be considered comprehensively when the A...

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Problems solved by technology

[0003] Although the actual response process of the system, the voltage quality and the actual constraints of the power flow can be considered comprehensively when the AC power flow method is used to evaluate the system state, the evaluation results are theoretically closer to the actual situation and the evaluation accuracy is higher. In the system risk assessment, the number of accidental accident states that may occur in the system is very large, and the analysis process of the system behavior after the accident is a set of nonlinear equations and nonlinear optimization solving problems. Therefore, to achieve the ideal accuracy, the calculation amount often reaches Unacceptable level, this is the main obstacle for the engineering application of the AC power flow method in the risk assessment of large-scale power systems, and it is also a difficulty in the risk assessment of large-scale power systems

[0004] Although the DC power flow cannot calculate the amplitude of the node voltage, and the active power flow also has some errors, compared with the AC power flow using the Newton-Raphson method or the P-Q decoupling method, the average error of the active power is not large (for the high-voltage power grid, the error Generally around 3-5%)

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