Advantages of Static var generator to Static var compensator
Jan 04,2020

SVG Principle

The principle of the SVG is, when the load is generating inductive or capacitive current, it makes load current lagging or leading the voltage. SVG detects the phase angle difference and generates leading or lagging current into the grid, making the phase angle of current almost the same as that of voltage on the transformer side, which means fundamental power factor is unit.

static var generator principle

Compared with SVC device, SVG/STATCOM has the following advantages:

  1. Using IGBT+DSP+FPGA technology, the system has high reliability, basically needs no maintenance, and can save a lot of maintenance costs;
  2. The performance in improving the system transient stability and the damping system oscillation etc is much better than that of the conventional SVC;
  3. Flexible control, faster adjustment speed, wide adjustment speed, continuous and rapid adjustment under inductive and capacitive operating conditions, the response speed can reach lower than 10ms(5ms);
  4. Static operation, safe and stable, no large rotating equipment like camera adjustment, no wear and no mechanical noise, it will greatly improve the life of the device and improve the environmental impact;
  5. The capacity of the capacitor is not high, and the large inductance and large capacitance in the conventional device and the huge switching mechanism can be omitted, so that the STATCOM has small volume and low loss;
  6. The connection reactance is small. The connection reactance of STATCOM connected to the grid is used to filter out the higher harmonics present in the current, and also to connect the converter to the grid. Therefore, the inductance of STATCOM is much smaller than the required inductance of SVC device with the same compensation capacity of TCR;
  7. The STATCOM output current is independent of voltage and exhibits constant current source characteristics with a wider operating range. The essence of SVC is impedance compensation, and the output current and voltage are linear. Therefore, the same capacity STATCOM can provide greater compensation capacity than SVC when the system voltage becomes lower;
    SVG principle
  8. STATCOM has a faster response speed than SVC and is therefore more suitable for suppressing voltage flicker. The STATCOM response time is within 10ms, while the SVC response time is generally 20 to 40ms. The STATCOM can be completed within 1ms from the rated capacitive reactive power to the rated inductive reactive power (or vice versa). This response speed is fully capable of compensating for the impact load;
  9. STATCOM's bridge circuit uses multiplexing technology, multi-level technology or PWM technology to eliminate lower harmonics and reduce the higher harmonics such as 7, 11 etc to an acceptable level. The SVC itself has to generate a certain amount of harmonics. For example, the TCR type has a large number of sub-harmonics of 5 and 7 times, accounting for 5% to 8% of the fundamental wave value; other such as SR, TCT, etc. also produce 3, 5, 7,11 and other high-order harmonics, which brings many difficulties to the filter design of the SVC system;
  10. STATCOM has better control stability than SVC under fault conditions. SVC uses a large number of capacitor reactors, which can cause instability when the external system capacity is comparable to the capacity of the compensation device. STATCOM is not sensitive to external system operating conditions and structural changes;
  11. STATCOM has a smaller footprint and lower cost than the same capacity SVC. STATCOM can reduce the capacitor volume by using DC capacitor energy storage, and can control the smooth change of reactive power without parallel reactor, so the installation size is greatly reduced;
  12. STATCOM can provide active power within a certain range and reduce active power impact. SVC can only provide reactive power and does not have the function of providing active power.
    ZDDQ statcom project
Send a Message
welcome to zddq
If you are interested in our products and want to know more details,please leave a message here,we will reply you as soon as we can.