Power quality overall solution
With the development of China's national economy, the increase of non-linearity, asymmetry and shock load in the power grid will have the following adverse effects:
1. The reactive and harmonic currents generated by the non-linear load penetrate into the power system in large quantities, which cannot be treated for a long time, which increases the loss of the system.
2. Rapid impact load (such as steel rolling mill, welding machine, large punch, etc.) absorbs reactive power from the power grid, at the same time generates voltage fluctuations and flicker, reduces the effective output of the motor, reduces the product yield, and shortens the service life of the equipment.
3. The asymmetric load exacerbates the imbalance of the power grid.
● In response to the above situation, Changsha Hengkai Electric Equipment Co., Ltd. launched the HK-ASVG intelligent integrated filter compensation device. This product combines advanced power electronics technology with traditional filter compensation methods and has the following functions:
Harmonic control function:
·2-51 times wide range filtering, filtering rate ≥95%;
·Neutral line harmonic elimination;
Balance three-phase current:
·Accurately adjust the three-phase current of the system;
·Reduce the neutral current;
Reactive power compensation:
·Bidirectional reactive output;
·Accurate reactive power compensation;
·Target power factor setting;
·Capacitor condition monitoring;
·Energy-saving working mode;
·Over-temperature derating function;
● HK-ASVG intelligent comprehensive filter compensation device has the following technical advantages:
The active filter unit directly controls the switching of the traditional filter compensation unit to avoid capacity hedging between the two.
For different working conditions, the active filter can be combined with common compensation capacitors, sub-compensation capacitors (L-N, L-L) and smart capacitors.
3.High cost performance:
The product makes full use of the economy of traditional filter compensation products and the advanced nature of power electronic products. The traditional filter compensation unit is for coarse adjustment of basic reactive power while absorbing some harmonics, and the active filter unit is for fast-changing reactive power demand and The harmonic current is finely compensated, and at the same time, the active filter unit reactive power bidirectional adjustment function can be used to effectively control the reactive power reverse transmission situation and make up for the innate deficiencies of the traditional filter compensation device.
Compared with pure power electronics solutions, HK-ASVG products replace most of the capacity with traditional filter compensation products. Because the losses of traditional products are much lower than the IGBT switching losses, the active filter capacity accounts for a small proportion, and the overall device loss is low.
HK-ASVG products have advanced fault-tolerant operation functions, that is, when an active filter unit or traditional filter compensation unit fails to exit, the control system automatically shields the failed unit to ensure the normal operation of other normal units; When the unit is shut down due to a transient fault, the traditional filter compensation unit can still operate independently.
● HK-ASVG intelligent comprehensive filter compensation device has multiple product combination methods:
1.Active filter + common complement capacitor
This scheme is suitable for industrial loads, with low power factor, serious harmonic pollution, and basic three-phase current balance. The traditional filter compensation unit compensates the basic reactive power of the system while absorbing a small amount of harmonic current; Harmonic current is controlled, and the active filter excess capacity can linearly compensate for rapidly changing reactive power to provide system power factor.
2.Active filter + sub-complement capacitor
This solution is aimed at the working conditions of residential electricity load, three-phase current imbalance, small reactive power demand or even reactive power reverse transmission. The compensation capacitor can be used to compensate the basic active and reactive unbalance. The three-phase current is roughly balanced and the system power factor is improved; the active filter unit is used to filter out the single-phase non-linear load to generate harmonic current, and at the same time, the reactive power fine compensation is used to realize the reactive power balance on the spot and the reactive power reverse control Finally, the three-phase current is accurately adjusted to achieve complete three-phase current balance, comprehensively solve the problem of power quality of distribution transformers, and ensure the safety of residents' electricity.