Static Var Generator (SVG) is essential in the power system, and its main function is to improve the power factor of the power supply and distribution system, thereby improving the utilization rate of transmission and transformation equipment, improving electricity efficiency, and reducing electricity costs;
in this post, we will talk about this Static Var Generator; firstly, we need to know two simple concepts;
Active power & reactive power
Active power
Active power is the electrical power required to maintain the normal operation of electrical equipment, that is, the electrical power that converts electrical energy into other forms of energy (mechanical energy, light energy, thermal energy).
Reactive power
Reactive power is the electrical power used to exchange electric and magnetic fields within a circuit, and to establish and maintain magnetic fields in electrical equipment. It does not work externally, but transforms into other forms of energy. Any electrical equipment with electromagnetic coils must consume reactive power in order to establish a magnetic field. For example, a 40 watt lamp requires not only more than 40 watts of active power to emit light, but also about 80 Var of reactive power for the coil of the ballast to establish an alternating magnetic field. It is called “reactive” because it does not work externally, and the units of reactive power is Var or kVar.
Basic principle of Static Var Generator(SVG)
To be simply , electrical equipment absorbs active and reactive power from the power source. If the reactive power is insufficient, the terminal voltage of the electrical equipment will decrease, affecting normal operation. Therefore, reactive power compensation is needed. The Static Var Generator(SVG) uses on-site compensation to reduce the reactive power provided by the power grid to the inductive load, thereby reducing the flow of reactive power in the power grid, Therefore, it reduces the energy loss caused by reactive power transmission on transmission lines and improves the operating conditions of the power grid.
Connect devices with capacitive power loads and inductive power loads in the same circuit; When capacitive loads release energy, inductive loads absorb energy; When the sensory load releases energy, the capacitive load absorbs energy; Energy is exchanged between two types of loads. In this way, the reactive power absorbed by the inductive load can be compensated from the reactive power output by the capacitive load, which is the basic principle of Static Var Generator(SVG).
Power factor:
The actual power load in the power supply and consumption system is not purely inductive or capacitive, but rather
A load with both inductance or capacitance and resistance. The voltage and current of this load
There is a certain phase difference between the phasors, and the cosine cosine of the phase angle cosq is called the power factor, also known as the force rate. It is the ratio of active power to apparent power;
Under a certain active power, the power factor cos φ The smaller the value, the greater the required reactive power. To meet the requirements of electricity consumption, the capacity of power supply lines and transformers needs to be increased. In this way, not only will it increase investment in power supply and reduce equipment utilization, but it will also increase line losses. In order to improve the economic operation efficiency of the power grid, artificial compensation of capacitive or inductive reactive power is used to offset the reactive power of the line based on the type of reactive power in the power grid.
Classifications of Static Var Generator(SVG)
1. Inductive reactive power: The current vector lags behind the voltage vector by 90 °, such as in electric motors, transformers, etc
2. Capacitive reactive power: The current vector is 90 ° ahead of the voltage vector, such as capacitors and cable transmission and distribution Lines, etc.
3. Fundamental reactive power: reactive power equal to the power frequency (50Hz)
4. Harmonic reactive power: reactive power that is not equal to the power supply frequency
Main functions of this static var generator (SVG):
The main function of Static Var Generator(SVG) is to increase power factor to reduce equipment capacity and power loss, stabilize voltage and improve power supply quality, improve transmission stability and capacity in long-distance transmission, and balance the active and reactive power of three-phase loads. Installing a parallel Static Var Generator(SVG) can limit the transmission of reactive power in the power grid, thereby reducing voltage loss of the line and improving the voltage quality of the distribution network.
Main components of a Static Var Generator(SVG)
it has Control cabinet, Starting cabinet, Power cabinet, Connecting Reactors and Cooling system etc.
The working mode of a Static Var Generator(SVG)
The constant device reactive power mode is used to control the output of reactive power by the device. The device outputs reactive power according to the set capacity. This method can measure the accuracy and step response speed of the device in tracking reactive power.
In constant power factor mode, the power factor control point can be set to control the power factor of the control point within the set target value or range.
The constant system reactive power mode can accurately control the system reactive power to the set target value.The voltage and reactive power comprehensive control mode is suitable for wind farms, photovoltaic power stations, power grids, and other situations where the voltage at the assessment point needs to be stabilized at a certain level. The device adjusts its reactive power output to stabilize the voltage at the assessment point within the voltage target value or range set by the user. When the voltage at the assessment point is lower than the voltage reference set by the user, the device outputs capacitive reactive power to increase the assessment point voltage; When the voltage at the assessment point is higher than the set value, the device outputs inductive reactive power to reduce the assessment point voltage. The target or range of controllable power factor or system reactive power when the voltage is qualified.
Advantages of a Static Var Generator(SVG)
SVG is a high-performance dynamic compensator used in power transmission and distribution systems, which is essentially a controllable synchronous power supply.
Compensating reactive power can achieve continuous smooth bidirectional adjustment
Will not cause system resonance or harmonic current amplification, with good safety and stability
Short response time, effectively suppressing flicker
Can provide fast reactive power changes required for low voltage ride through
Low operational losses and Modular design, simple operation and maintenance
Maintenance precautions of Static Var Generator(SVG)
Although the grounding of the Static Var Generator(SVG) startup cabinet and power cabinet is at a low potential
During SVG operation, the current limiting resistor, bypass contactor, and power inside the starting cabinet
All chain links inside the cabinet are of high potential. Therefore, it is strictly prohibited to open SVG during operation
Start the cabinet doors and power cabinet doors to avoid accidents. If you need to start the opposite direction
For maintenance of components inside the moving cabinet and power cabinet, the SVG higher-level circuit must be disconnected Only after disconnecting the SVG and grounding the isolation switch can the SVG be connected
Perform maintenance.
During SVG operation, dust is easily collected due to the suction of the SVG fan
Inhale the SVG power cabinet, therefore the dust prevention of the SVG power cabinet door should be regularly cleaned Filter cotton and regularly clean the dust on the chain links inside the power cabinet. In order to reduce
The impact of dust on SVG should be regularly cleaned in the dynamic reactive power compensation room
To meet the air intake requirements of the SVG room, regularly clean the air intake of the SVG room
Filter cotton to avoid damage to the cooling fan caused by insufficient air intake.
PowerTel and his expert engineers are capable of designing & manufacturing a custom Static Var Generator(SVG) used on solar power plants, wind power plants, oil & gas plaform, mining factories, power transmission & distribution lines, electrical substations, and all kinds of industrial factories.