1.1ANSVC low voltage reactive power compensation device introduction
ANSVC low-voltage reactive power compensation device is suitable for automatic reactive power compensation of frequency 50Hz voltage 0.4kV power grid; it integrates reactive power compensation and power grid monitoring, which can not only compensate the reactive power loss in the power grid by switching capacitor bank, but also improve The power factor reduces the line loss, thereby improving the load capacity and power quality of the power grid. At the same time, it can also monitor the three-phase voltage, current, power factor and other power parameters of the power grid in real time.
1.2 The importance of reactive power compensation
In general, the use of reactive power compensation devices to improve the power factor is reflected in two aspects: First, it can reduce the power loss on the transmission line; Second, the potential of power equipment (such as motors, transformers, etc.) can be fully utilized. Because the electric appliance always works under a certain voltage and a certain active power, if the power factor is low, a large current is used to ensure the normal operation of the electric appliance, and the transmission current becomes large, resulting in an increase in line loss. In addition, any power equipment always works within a certain rated voltage and rated current. If the rated voltage exceeds the rated voltage, it will threaten the insulation performance of the equipment. If the working current exceeds the rated value, the internal temperature rise will be too high, thus reducing the equipment. The service life. For some power generation equipment, the increase of power factor can greatly increase the efficiency. For example, if a generator has a capacity of 1500 kW, when the power factor of the power system is increased from 0.6 to 0.8, the actual power generation capacity can be increased to 3000 kW.
1.3 Benefits of reactive power compensation
● If the power factor is too low, it will be punished by the power sector or even interrupt the power consumption of the enterprise.
Industrial users with high voltage supply and power users with high voltage power supply with load voltage regulator, power factor is above 0.90. Other 100kVA (kW) and above power users and large and medium-sized power irrigation and drainage stations have a power factor of 0.85 or higher. For users whose power factor does not meet the above requirements, the power department will charge an additional electricity fee, namely: power rate electricity (fine).
●The lack of reactive power in the power system will result in lower production efficiency and higher production costs.
When the power factor is low, the voltage of the device changes greatly, the reactive power loss is also large, and the aging of the device is accelerated, which easily causes the service life of the device to be shortened and affects the operation of the device.
● Reduce line loss of transformers and electrical network equipment
The apparent power transmitted by the line is unchanged, and the low power factor will directly increase the loss of the transformer and the transmission line, directly increasing the power cost.
1.4 Implementation standards
GB/T7251.1-2013 "Low-voltage switchgear and control equipment Part 1"
GB/T14549-1993 "Power Quality: Harmonics in Utility Grid"
GB/T15543-2008 "Power Quality: Three-phase Voltage Allowable Unbalance"
GB/T18481-2001 "Power Quality: Temporary Overvoltage and Transient Overvoltage"
GB/T15576-2008 "General technical conditions for low voltage reactive power static compensation device"
2, product introduction
2.1 Working principle
The ANSVC low-voltage reactive power compensation device is connected in parallel throughout the power supply system, and can control the power capacitor switching to compensate according to the change of the load power factor in the power grid. The principle is as follows: ANSVC low-voltage reactive power compensation device collects current and voltage signals through CT, calculates the best solution of switching capacitors through the calculation of reactive power compensation controller, and controls the switching of each group of power capacitors through non-contact switches. As shown below:
2.2 Model Description
2.3 technical parameters
2.4 Product Features
●The cabinet body adopts frame-assembled structure, surface sprayed or passivated, and the appearance is neat and beautiful, anti-aging, anti-corrosion and high life.
●The structure design is compact and reasonable, modular design, neat and tidy wiring, and easy to maintain.
● The cabinet body can be installed independently or in combination with other cabinets.
● A variety of compensation forms: three-phase total compensation, three-phase compensation, total compensation + sub-complement three forms. According to the actual situation of the power grid, taking into account the compensation effect and cost, the compensation form should be selected reasonably. Fully resolve the contradiction between compensation reactive power and three-phase imbalance and between three-phase compensation and cost.
● Use series reactor protection capacitors, which can be customized according to the specific grid background of the user site.
● The controller has multi-loop loop or code switching operation mode, which can effectively avoid the problem that the individual capacitors are switched too frequently during group switching and achieve optimal control.
● With data acquisition function and standard communication interface, it can realize remote real-time monitoring and computer network management.
●The non-contact switch is used for switching capacitance, zero-crossing input, neither switching the inrush current and good heat dissipation mechanism, and no harmonic injection is generated, and the reliability is high.
● With power parameter monitoring, acquisition and statistics functions.
2.5 Structure and size
3, product application
3.1 Analysis of application areas
In AC power systems, the vast majority of loads are inductive loads. The inductive reactive power generated by it flows back into the power system, causing the system power factor to decrease, and the voltage drop of the system to increase the power loss. Common load power factors are as follows:
Common load power factor table
As can be seen from the above table, inductive loads are very common. In order to minimize losses, the power supply department will require power users to minimize reactive power consumption. Power capacitors have the opposite effect on inductive loads, so inputting appropriate capacitive reactive power can not only improve the power factor, but also increase the system voltage, and can effectively reduce system power loss. Therefore, most users are currently using capacitors for reactive power compensation.
ANSVC low-voltage reactive power compensation devices are widely used in electric power, automotive, metallurgy, railway, petroleum, port, light industry, machinery manufacturing, chemical, paper, textile, coal, shipbuilding, communications, building materials, airports, large venues, high-rise buildings, etc. In the place distribution system, it is especially suitable for electric welding machines, air hammers, injection molding machines, internal mixers, intermediate frequency furnaces, rolling mills, cranes, elevators, driving vehicles, etc. where special reactive power compensation is required.
3.3 Example above
Total complement module Sub-complement module:
3.4 application case
The ANSVC low-voltage reactive power compensation device is used in places where the reactive power demand is large, and the load amplitude and frequency fluctuation are small. The metal smelting industry is mainly used for various types of heating furnaces, which is very suitable for the application of ANSVC low-voltage reactive power compensation devices.
A large metal processing enterprise in Shanxi mainly focuses on melting carbon steel and special steel. A large-scale medium frequency induction heating furnace was used in the factory.
After on-site measurement, the ANSVC-600-380/B reactive power compensation device is configured for the customer, and the compensation effect is as follows:
3.5 typical industry case
The above data is the specific field test results, the same industry load conditions are different, the current harmonic total distortion rate (THDi) is also different, the above THDi value is for reference only.