Improve power factor and reduce line loss
Stabilize system voltage,reduce voltage fluctuation
Restrain and eliminate harmonic 

Application industrial fields

Rolling Mill

The big reactive impulsion caused by rolling mills and other industrial symmetric loads may lead to the following problems to the power grid:

• The voltage drop and fluctuation, which may result in malfunction of electric equipment and reduce the productive efficiency.
• Low power factor
• The harmful high-order harmonic waves in the driving devices, typically 5th, 7th, 11th, 13th and side-frequencies, which will cause serious voltage distortion.

Electric Arc Furnace (EAF) and Ladle Furnace

The electric arc furnace and ladle furnace are typical non-linear and erratic loads in the power grid, causing a series of adverse effects to the power grid:

• Result in serious three-phase unbalance of the power grid, and cause negative-sequence currents.
• Produce high order harmonics, such as coexist of 2nd, 4th even harmonics and 3rd, 5th, 7th odd harmonic, which make severe voltage distortion become more complicated.
• Serious voltage flickers
• Low power factor

Electric Railway Traction Substation

While protecting the environment, the electric locomotive also causes serious pollution to the power grid. As the electric locomotive is powered by single phase power system, which not only causes serious three-phase unbalance and low power factor but also generates negative-sequence currents. Currently, the only way to solve the problem is to install SVC system at appropriate locations along the railway. The SVC is able to balance the three-phase by means of single-phase compensating and to increase the power factor through filter capacitor. Wanlida’s SVC is capable of solving this problem perfectly at minimum cost.

Hoists and Other Heavy Industrial Loads

The hoists and other heavy industrial loads may cause the following effects to the power grid when they are at working state:

• Cause the voltage drop and voltage fluctuation in the power grid.
• Low power factor
• The harmful high-order harmonic currents

Wanlida’s SVC can solve above problems perfectly and help customers obtain the following benefits:

• Increase the power factor by dynamic reactive power compensation
• Eliminate the voltage distortion caused by harmonic
• Stabilize the voltage and reduce the voltage fluctuation and flicker
• Balance the three-phase load current and eliminate the negative sequence current
• Increase the operation safety of impact loading equipment and its adjacent electrical equipment

Long Distance Power Transmission

The power grid tends to have larger capacity and longer distance, in the case of long-distance AC transmission, due to the influence of Ferranti Effect, the voltage in the middle of transmission lines will rise which will limit the transferred power. The capacitive power along the long distance power transmission lines is in proportion to the cable length and the square of voltage, so it will be terribly surprising for capacitive current power to ground, which results in the voltage rising of 1.5 to 2 times of rated voltage at the end of transmission line and then causes badly result. The power utility usually install shunt reactor to compensate capacitive current to ground to solve voltage rising at the end of transmission lines, but if the shunt reactor is of fixed capacity, it will be removed from compensation system once inductive current is over desired capacitive current to ground. As usual, the operation of shunt reactor connected in parallel to transmission line wants a very high demand for switch, but until now, it is still very difficulty to solve the over-voltage surge caused by reclosing of switch, as a result, it results in bad over-voltage accidents. However, the SVC of MCR type of Wanlida can solve those problems; it can regulate reactive power of transmission line dynamically and fast. The SVC of TCR can not be directly installed in transmission lines with over 35KV, but the SVC of MCR can be installed in extra-high voltage and ultra-high voltage transmission lines directly, and it has no need of action of switching. So the SVC of MCR type is able to improve transmission and distribution performance of the power system remarkably. It should be installed at one or several proper points in the power grid in order to maintain a balanced voltage under different conditions and achieve the following purposes:

• Stabilize voltage of a weak system
• Reduce the transmission losses
• Enhance transmission capability and make existing power grid more efficient
• Improve transient stability
• Increase the resistance in the small interference
• Improve system damping
• Enhance the voltage control and stability
• Restrain the power oscillation and the sub-synchronous resonance

Wind Power Plant

The output power of generator is always fluctuated frequently because of variable wind power. At present, the popular asynchronous wind generator (including Doubly-Fed Type) needs to absorb parts of inductive reactive power to build magnetic fields, the paralleled capacitor banks can realize compensation, but the stepped switching capacitor banks can not meet fast and dynamic reactive power compensation demand caused by variable wind power, sometimes, if the capacitor banks can not meet reactive power compensation in time, the wind generator will absorb reactive power from the upper power grid, which will result in low power factor of upper power grid and then cause voltage fluctuation, so the state grid put forward the < Regulations on State Grid Corporation Wind Farm Grid Access Technology (Amendment)> based on voltage fluctuation, flicker, frequency deviation, harmonics and lacking reactive power.

The SVC of MCR can solve the above problems to meet the demand of utility.

Secondary Substation (66KV to 110 kV)

In the regional power grid, the stepped switching capacitor banks are used to compensate the system reactive power and increase the power factor. But they are only able to provide the capacitive reactive power, and unable to realize rapid and accurate adjustment according to the load variation, so sometimes they provide much more reactive power than the actual desired reactive power, which will result in over voltage of the bus bar and damage the electric equipment and destroy system stability.

Because the SVC of TCR can not be directly installed in subtransmission lines with over 35KV, Wanlida’s SVC of MCR will be most suitable for subtransmission, Wanlida’s SVC system is able to compensate with capacitive and inductive reactive power rapidly and accurately. It solves the problems of reactive feedback effectively. In addition, when a new SVC system is installed, the existing fixed capacitor banks can be utilized by adding a MCR, which requires the minimum investment. It is the most effective way to improve the power quality of the local power grid, the detail benefits is as below:

• Reduce the reactive power exchange with system and improve system stability
• Rapidly and continuously compensate the reactive power, increase the power factor and improve the power quality.
• Reduce the power losses of distribution system
• Used in combination of stepped switching capacitor banks to reduce the damage caused by frequent switching of capacitor bank.