Method and system for judging direction of power factor

Abstract

The invention discloses a power factor direction judgment method and system. The power factor direction judgment method includes the steps: acquiring the power up state of a reactive compensation device; when the reactive compensation device is converted into the power up state from the power off state, acquiring the current active power and reactive power; according to the active power, setting aflag bit; and finally according to the active power, the flag bit and the reactive power, judging the direction of the power factor. The power factor direction judgment method and system can correctly judge the direction of the power factor no matter whether a current transformer accesses the right direction, thus guaranteeing correct input of reactive compensation.

Description

technical field [0001] The invention relates to the technical field of power grid reactive power compensation, in particular to a method and system for judging the direction of power factor. Background technique [0002] With the rapid development of modern industry, the quality requirements of electric energy are getting higher and higher, and the balance of reactive power is an important guarantee for the quality of electric energy. At present, most of the power loads in the power grid, such as asynchronous motors, transformers and other equipment, are inductive loads. During operation, they not only consume active power, but also absorb a certain amount of reactive power from the power grid, resulting in deviation of the power factor of the power grid. Low. Under the premise of maintaining a certain active power, the smaller the power factor of the line, the greater the current flowing on the line, resulting in greater voltage drop and loss on the line. In severe cases,...

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Problems solved by technology

[0006] However, specifying the direction of the current transformer can of course solve the problem, but it does not ensure that everyone who installs it is a professional, let alone that everyone reads the instructions carefully and operates step by step. Ensure that the direction of the primary current transformer is correct. For sub-compensation, if the direction of the star point is wrong, it will be more troublesome; and the method of adjusting the direction of the power factor by using the program to detect the lead and lag of the power factor through power-on, There are also certain disadvantages, because the power factor cannot be guaranteed at the moment of power-on, and the power factor must be lagging. For example, when the current load is relatively small and the local compensation happens to be used, the power factor becomes leading, and the direction is changed at this time. , when the real load comes up, the lag becomes leading again, which will lead to the situation that the capacitor cannot be switched on

Therefore, none of the above methods in the prior art can ensure that the direction of the power factor is accurately judged when the direction of the current transformer is reversed, resulting in the reactive power compensation controller being unable to correctly control the input and removal of the power capacitor, failing to achieve the desired Reactive power compensation effect

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