Method and device for monitoring short-circuit capacity on line based on dynamic transfer impedance

Abstract

The invention relates to a method and a device for monitoring short-circuit capacity on line, in particular to the method and the device for monitoring the short-circuit capacity on line based on dynamic transfer impedance. The method comprises the following steps of: (A), replacing the conventional form of a single power supply of an equivalent target of a power system with a form of a multi-power supply to a single load node; (B), computing a pure network admittance matrix of a system according to the power grid topology information, and converting the pure network admittance matrix into an order increasing form in an X-Y coordinate; (C), aiming at power supply nodes and a load node, amending the network admittance matrix; (D), computing the dynamic transfer impedance from each power supply node to the load node; and (E), computing the internal electric potential of each power supply node according to the measured values of a power angle, terminal voltage, terminal current and the like of a motor in the running process of the system, thus computing the short-circuit capacity value of the nodes. As the method and the device are based on the dynamic transfer impedance, the change of the short-circuit capacity of the nodes can be traced quickly and precisely without any hypothesis or approximation, and the method and the device have promotional and applicable value.

Description

technical field [0001] The invention relates to a short-circuit capacity online monitoring method and a device thereof, in particular to a dynamic transfer impedance-based short-circuit capacity online monitoring method and a device thereof. Background technique [0002] The short-circuit capacity is defined as the product of the three-phase short-circuit current of the bus in the power system and the rated voltage. The short-circuit capacity directly marks the voltage strength of the system. A large short-circuit capacity indicates that the network is strong, and switching of loads, shunt capacitors or reactors will not cause large changes in voltage amplitude; on the contrary, a small short-circuit capacity means that the network is weak. Therefore, in order to evaluate the voltage stability level of the power system and ensure that the system operates in a sufficient voltage stability region, it is of great significance to determine the short-circuit capacity at the node ...

AI Technical Summary

Problems solved by technology

[0007] Another purpose of the present invention is to solve the technical problems existing in the prior art that the Thevenin equivalent directly equates the system side to a single power supply plus equivalent impedance, which cannot reflect the influence of a single power supply point on the voltage stability of the load node; provide A short-circuit capacity based on dynamic transfer impedance can be determined to determine the contribution of different power points to the short-circuit capacity of the load point, thereby effectively reflecting the voltage support capability of different power sources to the load point, and providing effective guidance for subsequent voltage stability analysis and control. On-line monitoring method and device thereof

Images