Parallel Active Power Filter (PAPF)

1. Brief introduction of parallel active power filter (PAPF)
Rongxin Power Electronic Company has long been committed to the researching, developing, manufacturing, designing and customer service of power quality equipment, Static VAR Compensators (SVC), HVC, locomotive-driven frequency converter, VFS, MABZ and other power electronic equipment. We have thus accumulated abundant experience and achieved remarkable accomplishments in contributing to the energy conservation and production safety of industrial and mining enterprises.

Our parallel active power filter has its own independent intellectual property and a cost performance ration superior to that of like imported products. With intelligent DSP controlling the chips and high speed IGBT modules, and real time detection based on the instantaneous reactive power theory, PAPF can compensate harmonic wave in real time and solve the common problems of power quality such as imbalance of reactive power and current, voltage flicker, etc. In this way, PAPF ensures the economical and safe operation of industrial and mining enterprises.

2. Problems solved by parallel active power filter (PAPF)
Due to a large amount of non-linear power electronic equipment, impact and fluctuating loads (such as that of arc furnace, heavy merchant mill and electric locomotive, etc), problems of power quality have become more and more serious with each passing day. Sometimes, they even threaten the normal operation of power system and user equipment. Highly automatic electric equipment, in particular, causes enormous economic loss every year owing to problems of power quality. According to the causal factors and concerned party, problems of power quality can be divided into quality problems by power supplier and quality problems by power consumer.

(1)Common problems caused by power supplier
Quality of supplied power primarily refers to the voltage quality and reliability of supplied power.

A. Voltage sag and voltage swell
B. Voltage fluctuation
C. Voltage harmonics
D. Voltage three-phase imbalance
Among problems caused by power supplier, damage of voltage sag is rated to be the most serious.

Damage of voltage sag
A. The automatic production line of certain manufacturing industry can be brought to a standstill, production equipment subjected to failure and waste produced by voltage sag.
B. Automation system of business users may be caused to be out of order and customer information to be lost.
C. Voltage sag may lead to sudden stoppage of public facilities and going out of lighting fixtures, undermining public order and endangering human safety.

(2) Common quality problems caused by power consumer
Quality of consumed power refers to that of current drawn from power gird. A. Reactive current
B. Current harmonics
C. Current three phase imbalance
Among quality problems on part of power consumer, damage caused by current harmonics dominates.

Damage of current harmonics
A. Current harmonics lead equipment of public utility grid to extra power consumption. Besides, they lower the efficiency of power generating equipment, power transmitting equipment and power driven equipment. In three phase four wire system, zero line may be overheated or causes fire disaster as a result of excessive harmonic current going through the zero line three times or times that of three.
B. Current harmonics affect the normal operation of various electrical devices, heat the electric rotating motors (generator and electromotor) and cause pulsating torques and noise. Part of the transformer may be severely overheated. What’s more, overheating, insulation aging, life span shortening or even destruction of capacitors and cables may also occur.
C. Current harmonics may result in failure to operate and malfunction of protective relaying equipment and automatic controlling device. Besides, measurement inaccuracy of electrical measuring instrument may arise.
D. Current harmonics pose interference to the communication system in the neighborhood. If you are lucky, you only have your communication quality lowered. If not, you will have the information lost and breakdown of your communication system.
E. Current harmonics may lead to partial parallel resonance and series resonance of public utility grid, thus amplifying harmonic waves. As a result, damage listed above will drastically deteriorate and even fatal accidents may occur.

3. Advantages of parallel active power filter (PAPF)
There have been two ways to solve the harmonic wave problems existent in the power system, i.e. by active filter and by passive filter.

(1)Disadvantages of the passive filter
A. A parameter is limited to compensation for a specific number of harmonic waves.
B. The passive filter has a low response speed, thus incapable of dynamic compensation for harmonic waves.
C. In the process of harmonic compensation, unwanted reactive power may be produced.
D. The passive filter alters the impedance of the system, and thus is likely to bring about resonance.
E. As the parameters have low stability and capacitance parameters, in particular, are liable to variation, detuning can thus easily occur.
F. Higher harmonics will be amplified as a result of compensating a certain order harmonic wave.

(2) Advantages of the active filter (APF)
A. One active filter is suitable for various nonlinear loads.
B. With the response time only a few milliseconds, the active filter is capable of dynamic compensation for harmonic waves.
C. The active filter will not change the impedance after it is connected to the power system.
D. Harmonic compensation will not be contradictory to reactive power compensation, as the active filter can compensate harmonics at the same time of compensating reactive power.
.Therefore, adoption of the active filter is the best way to solve harmonic pollution and improve the quality of supplied power.

4. Field of application
⑴The parallel active power filter (PAPF) can be applied to three phase four wire equipment in commercial buildings.
a. Office buildings and commercial mansions
b. Schools and hospitals
c. Mobile communication
d. Residential buildings
e. Computing information centre
(2)The parallel active power filter (PAPF) is also used in three-phase three wire equipment for industrial load.
a. Automobile manufacturing
b. Rail transportation
c. Electric arc furnace
d. Chemicals and pharmaceuticals
e. Power electronics
f. Papermaking and printing

5. Technical features
As lively emerging technology, Rongxin parallel active power filter (PAPF) has a number of technical characteristics as follows.
(1)Real time follow up and dynamic compensation
Our parallel active power filter (PAPF) can automatically trace and compensate the variational harmonic current in power grid and has high controllability and quick response. Besides, the compensation of our PAPF is not affected by frequency jitter of power grid, and filtration is free from interference of system impedance. In this way, resonance caused by system impedance can be saved.
(2)Versatile function and synchronous handling of many power quality problems
The parallel active power filter (PAPF) is capable of settling many common power quality problems at one time, such as current harmonics, voltage flicker and impermissibly high power factor, etc. Therefore, PAPF is able to improve power quality and ensure safe and reliable operation of user equipment. Moreover, it both reduces power consumption and increases the working efficiency of user equipment.
(3)Power unit with modular design
Power unit has modular design of IGBT full bridge PWM inverter, and identical modules are interchangeable. Wit ha drawer-like structure, our PAPF is easy to easy to maintain and convenient to exchange. Thus reliability and maintainability of the PAPF can be largely improved. In addition, our PAPF features small size, high efficiency and high reliability.
(4)DSP intelligent control
Our parallel active power filter (PAPF) is equipped with high speed DSP chip to ensure accurate and effectual signal detection and compensation. Meanwhile, it also has monitoring function and automatic fault diagnosis and is flexible in operation. Operating parameters and operational status can thus be conveniently queried.
(5) Small in size and light weight
Our parallel active power filter (PAPF) is small in size and light in weight, as there is no need of high-voltage large-capacity energy storage element or filter accessories.
(6)Technical design of heat pipe dissipation
Heat pipe dissipation technology of Russian space flight and aviation is applied to power devices like IGBT modules of our parallel active power filter (PAPF), which has much higher efficiency in heat dissipation. As a result, heat island effect of high power devices is completely resolved and reliability of PAPF is greatly enhanced.
(7) Safe isolation
Fiber optic isolation is adopted between high voltage major circuit and controllers, thus realizing safe and reliable operation.
(8)Consummate protection and diagnosis
Our parallel active power filter (PAPF) has a perfect system of protection and fault diagnosis and you can consult, store and print through it.

Rongxin PAPF serial products are widely applied in the power distribution network of industries, business and government organizations, such as power system, coal mine enterprises, water treatment equipment, electrified railway and high buildings, etc.
Our parallel active power filter (PAPF) has remarkable capacity in resolving the following problems.
(1)Harmonic current
The PAPF can handle harmonic current in electric arc furnaces, electromotive and SCR converters, etc.
(2) Voltage flicker
The PAPF is used to deal with voltage flicker in electric welding equipment, punching machines, cranes and elevators, etc.
(3)Three phase imbalance
The PAPF is applied to solve the three phase imbalance in lighting equipment, induction furnace, welding machines, etc.
(4)Reactive power
The PAPF can handle the reactive power in asynchronous electromotor, transformers and transducers, etc.

6. Technical parameters