English
In our power supply and distribution system, reactive power is very important for the safe and effective operation of power supply and distribution system and load. What we usually call Reactive power compensator is to provide reactive power to the system where reactive power is needed. Reactive power compensator is essential in the system. Its main function is to improve the power factor of power supply and distribution system, improve power efficiency and reduce power cost; In addition, in long-distance transmission lines, adding dynamic Reactive power compensator devices at appropriate locations can also improve the stability of the transmission system, improve the transmission capacity and stabilize the voltage at the receiving end and the power grid. So how should we choose Reactive power compensator device? Is it better to be dynamic or static?
The following is a list of contents
Method of generating reactive power
How to select reactive power compensator device
There are three ways to generate reactive power
The first type is the early synchronous condenser, which is huge in volume and high in cost, and has been gradually eliminated.
The second is the method of shunt capacitor. The biggest advantage is that it has low cost and is easy to install and use. However, it needs to be designed according to the power quality problems such as harmonics that may exist in the system and the conditions such as power supply, load and voltage level of different users. Due to a large number of harmonics in the system, the LC tuned filter compensation device composed of capacitors and series reactors needs large capacity input to ensure the safety of capacitors, but at the same time, it may also cause the system to be over compensated and capacitive. Therefore, the so-called static power compensation device SVC was born.
The third is that with the development of power electronics technology, especially the emergence of high-voltage IGBT devices and the improvement of control technology, there is another reactive power source different from the traditional reactive power source based on capacitors and reactors, that is, SVG, i.e. static var generator. It is a reactive current source, which is controlled by PWM pulse width modulation technology, Make it emit reactive power in a capacitive manner; Or absorb reactive power, which is inductive. Since SVG does not use a lot of capacitors and adopt the multiplex technology, multilevel technology or PWM technology of bridge converter circuit for processing, it is not necessary to consider the harmonics generated by itself in the traditional SVC device; At the same time, it is not necessary to calculate the impedance in the system. At the same time, compared with SVC, SVG has the advantages of small volume, more rapid continuous dynamic and smooth regulation of reactive power. However, due to the high price of power devices, the capacity of SVG can not be large, and the price of the device is also high. At present, it is more suitable for customers with small system capacity and high requirements for fast dynamic response, especially for customers with two-way Reactive power compensator requirements.
From the above description of various Reactive power compensator devices, it is not difficult to see that fixed compensation refers to FC, that is, the compensated capacitor bank cannot increase or decrease the compensation capacity with the change of system load; Automatic compensation refers to the capacitor bank switched by the contactor or the capacitor bank TSC switched by the thyristor. It can be automatically adjusted according to the reactive power demand of the system through the power factor compensation controller, but the automatic adjustment is step-by-step, which is carried out according to a certain step length and cannot be carried out continuously without poles; The reactive power dynamic compensation device refers to the static Reactive power compensator devices such as SVC and SVG. The so-called static type refers to the switching devices in the automatic compensation device. When SVC and SVG are used, there is no switching device action. However, at present, in the eyes of users, because the thyristor switch in TSC also has no switching action and fast response speed, it is sometimes called TSC as dynamic compensation equipment.
For the final user, it is suggested to choose the appropriate compensation control mode according to their own load characteristics, rather than blindly using high-tech products. On the contrary, no matter what technology products are used, the internal components are particularly important, because the final device operation, control technology is on the one hand, on the other hand, the high quality of devices is also a necessary condition for safe and effective operation.
Zhuhai Sinopak Electric Ltd. provides high-quality STATCOM. If you are interested in our products, please contact us:daniel.wu@sinopakelectric.com.
You can visit us at https://www.powerqualitystatcom.com/
