The Importance of Reactive Power Compensation in Power Distribution System

There are many forms of electric loads in the grid, including capacitive loads and inductive loads. Under steady-state operating conditions, the grid needs to provide corresponding reactive power to these devices. When the reactive power demand in the system increases, the power plant To increase reactive power output through phase modulation, since the capacity of the generator is limited, it is necessary to reduce the output of active power, that is, to reduce the output capacity of the generator. In order to meet the requirements of electricity consumption, power generation The capacity of machine, power supply line and transformer needs to be increased, which will not only increase power supply investment, reduce equipment utilization, but also increase line loss.

In order to reduce the reactive power supply pressure of the power plant, it is necessary to invest in corresponding capacitors in the power supply system where the inductive load consumes a lot to provide reactive power for the inductive load, which greatly reduces the reactive power supply pressure of the power plant. With the development of society and the advancement of technology, more and more attention has been paid to the application of reactive power compensation in the field of distribution network. In order to minimize the transmission loss of reactive power and improve the efficiency of power transmission and distribution equipment, the configuration of reactive power compensation equipment should be planned and rationally arranged according to the principle of “level compensation, local balance”.

Based on years of practical experience, Shanghai Huijue Network Communication Equipment Co., Ltd. has launched a variety of reactive power compensation equipment for customers to choose from.

The most widely used at present is to use shunt capacitor series reactor, because the price is relatively cheap. The role of the series reactor is to limit the closing inrush current and suppress high-order harmonics. Among them, the switching switch can be a contactor, a composite switch or a thyristor switching switch.

According to whether there is a three-phase imbalance in the power system, three-phase co-compensation, separate compensation, and mixed compensation can be used to solve the problem of over-compensation and under-compensation.

Of course, there are static var compensation devices (SVC), which use thyristors as solid-state switches to control the capacity of reactors and capacitors connected to the system; and static var generators (SVG), which use shut-off The power electronic device (IGBT) forms a self-commutated bridge circuit, which is connected in parallel to the power grid through a reactor, and properly adjusts the amplitude and phase of the output voltage on the AC side of the bridge circuit, or directly controls the current on the AC side, which can quickly absorb or Generate the required reactive power to achieve the purpose of fast and dynamic adjustment of reactive power.