Power grid system, disconnection device and disconnection control method thereof

Abstract

The invention discloses a power grid system, a disconnection device and a disconnection control method thereof. The disconnection control method is applied to the disconnection device installed in a power grid system with water and electricity grid connection. The method comprises the following steps of obtaining a phase voltage of a hydroelectric generating set in a small grid-connected hydropower station; determining whether a voltage change amount of the phase voltage is greater than a preset value; if the voltage change amount is greater than the preset value, determining whether the phasevoltage exceeds a protection threshold; if the phase voltage exceeds the protection threshold, outputting a tripping control signal to a relay module in the disconnection device so that the relay module disconnects a connection switch between the hydroelectric generating set and a power grid system; and if the voltage change amount is not greater than the preset value, updating the protection threshold according to the phase voltage. Real-time adaptive dynamic adjustment is performed on the protection threshold based on the phase voltage within a reasonable fluctuation range to ensure rationality of the protection threshold and timeliness of adjustment, the system, the device and the method are effectively suitable for a variety of operating conditions of the power grid system and operation safety of the power grid system is ensured.

Description

technical field [0001] The present application relates to the field of power grid technology, and in particular to a power grid system, a decoupling device and a decoupling control method thereof. Background technique [0002] The mountainous power grid is rich in hydropower resources, and a large number of substations are connected to the grid. Small hydropower stations are mainly connected to the grid through 10kV lines, and most of the Ts are connected to 10kV feeders. developmental models such as figure 1 shown. In this mode, in the sending end system, the generators are connected to the substation in series, the transmission power on the 10kV feeder is reduced or the power is sent up, and the reactive power output of the small hydropower is supported, so that the voltage at each load node along the feeder is raised (U A < U B < U C ). Therefore, the voltage at the back end of the distribution network tends to fluctuate greatly with the change of operation mod...

AI Technical Summary

Problems solved by technology

In the existing technology, the protection threshold of the de-loading device is mostly a fixed value, which needs to be manually set by the relay protection staff or the power station maintenance personnel, so the timeliness of the modification of the protection threshold is poor, and it cannot be operated with the power grid Reasonable adjustments are completed in a timely manner for changes in the mode, resulting in problems such as misoperation or refusal of the unloading device

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