Power generator forced excitation control method under condition of power system faults

Abstract

The invention discloses a power generator forced excitation control method under the condition of power system has faults, and the method comprises the following steps that power generators with large installed capacity and high excitation response are selected from a power system, and forced excitation controllers are arranged to the power generators; and when the working system has faults, all power generators in the system are classified into an S cluster and an A cluster according to the power-angle information of the power generators which is measured in a phase measuring unit in a wide area measuring system, and equivalent power angles of the whole system are calculated. The forced excitation startup / exit moments of all power generator units are determined by integrating the clusters that the power generators are located in according to the change rules of the equivalent power angles. According to the power generator forced excitation control method under the condition of the power system faults, the power generator forced excitation is started / shut up in a gradual swing mode according to the swinging frequency of a transient stable process of the system, so that enough forced excitation control force is applied to key swinging frequency on the one hand and partial power generator forced excitation does not over-brake the follow-up swinging frequency of the system on the other hand, and the role of the power generator forced excitation control in improving the transient stability of the system can be fully displayed.

Description

technical field [0001] The invention belongs to the technical field of power system control, and in particular relates to a generator forced excitation control method in the case of a power system failure. Background technique [0002] The power system is a unified whole composed of generators, transformers, converters, power lines and various electrical equipment that produce, transform, transmit, distribute and consume electric energy. The ability of each synchronous motor to maintain synchronous operation and transition to a new or return to the original steady-state operation mode after a large disturbance in the case of a power system fault is called the transient stability of the power system by the industry. [0003] Generator excitation control is an effective measure to improve the transient stability of the power system; when a short-circuit fault occurs in the AC system, the generator terminal voltage drops, the output electromagnetic power decreases, and the inpu...

AI Technical Summary

Problems solved by technology

Forced excitation unit, forced excitation control amount, forced excitation start and exit time are the main factors affecting the effect of forced excitation control. Incentive control may be detrimental to system stability

[0006] Bayne J P et al. proposed in the literature titled Static exacter control to improve transient stability (IEEE Trans on Power System, 1975, PAS-94(4): 1141-1146) that the start-up logic of generator strong excitation is generally the generator terminal voltage The sudden drop exceeds a certain limit and the generator speed deviation also exceeds a certain limit; when using this forced excitation logic, on the one hand, only the units near the short-circuit point can obviously feel the impact of the fault and start the forced excitation control. The strong excitation control is usually not activated when the disturbance is small. Since there are fewer units actually participating in the forced excitation control during the fault period, the improvement effect on system stability is relatively limited; on the other hand, if there is a DC inverter station near the short-circuit point , after the fault, the power angle of the power grid unit at the sending end is positively shifted relative to the power angle of the unit at the receiving end grid, and the forced excitation logic will lead to strong excitation of the power grid unit at the receiving end, which is not conducive to the transient stability of the system

[0007] In the paper titled "Research on Improving the Transient Stability of Power System by Additional Intermittent Control of Generator Excitation" (Journal of Tsinghua University, 1980, 20(3): 43-51), Liu et al. After that, the forced excitation will be exited immediately, but the end time of the first pendulum of a unit in the system is often different from the end time of the first pendulum of the system, so from the perspective of the stability of the whole system, this method is also important for the selection of the exit timing of the forced excitation. not optimal

Images