English
In general, STATCOM is a solid-state switching converter. When its input end is connected with a power supply or energy storage device, its output end can independently send or absorb controllable active and reactive power. Compared with traditional reactive power compensation devices, STATCOM has the advantages of continuous regulation, small harmonic, low loss, wide operation range, high reliability and fast regulation speed. Since its inception, STATCOM has received extensive attention and rapid development. This article will briefly introduce the working principle of STATCOM.
The working principle of STATCOM
The features of STATCOM
The Static synchronous compensator uses the power electronic device of voltage source converter to generate reactive power. The voltage source converter converts the DC voltage into three-phase voltage with required amplitude, frequency and phase. Depending on the required output power and voltage, the voltage source converter can be two-level or three-level. It can be seen from the name of the Static synchronous compensator that the Static synchronous compensator has similar performance to the synchronous condenser, but as an electronic equipment, the Static synchronous compensator has no inertia, so it is better than the synchronous condenser in some performance aspects, such as fast dynamic response, low investment cost, low operation and maintenance cost.
Static synchronous compensator is a voltage regulating device based on voltage source converter (IGBT). It acts as a source or sink of reactive power independent of AC system voltage. STATCOM can operate as part of flexible AC transmission system (FACTS) to detect and compensate voltage fluctuation or flicker in real time, correct unbalanced load and control power factor.
The main circuit structure of STATCOM is composed of large capacitance at DC side and VSI based on power electronic devices, which is connected to the power system through reactance. U1 is to equivalent the output of STATCOM to a controllable voltage source under ideal conditions (i.e. ignoring the loss of line and STATCOM), and us is the ideal voltage source equivalent to the system side, and the two phases are consistent. When U1 jumps us, the phase of the current flowing from the system to STATCOM is 90% ahead of the system voltage, and capacitive reactive power is output; Similarly, when U1 is about us, the current flowing from the system to STATCOM lags behind the system voltage by 90% and outputs inductive reactive power. When U1 = us, the current between the system and STATCOM is zero, and there is no reactive power exchange between them. This is the ideal working state. In fact, US and U1 generally have an angle difference peck. By controlling us and peck, the reactive power emitted or absorbed by STATCOM can be adjusted.
With the advent of Static synchronous compensator, its superior performance can also be applied to the following aspects:
1) Dynamic voltage control in transmission and distribution system;
2) Power oscillation damping in transmission system;
3) Improvement of transient stability of power system;
4) Active power and reactive power control. It not only has the ability to control reactive power, but also can control active power (DC power supply can be obtained) if necessary.
5) Small size (compact electronic converter replaces passive components);
6) Factory modular products (reducing installation and commissioning time);
7) The encapsulated electronic converter is adopted (reducing the impact of the environment on the equipment).
Zhuhai Sinopak Electric Ltd. provides high-quality STATCOM. If you are interested in our products, please contact us:daniel.wu@sinopakelectric.com.
