Description

Power electronic equipment is increasingly used in industrial and commercial applications, such as: variable frequency speed control equipment, rectifiers, uninterruptible power supply UPS, DC power supply, welder, computer, television, energy-saving lamps, copiers, etc. These non-linear loads, while facilitating people’s production and life, generate a large amount of harmonics which are injected into the power grid, causing distortion of current and voltage waveforms, degrading power quality, and damaging the power grid and other equipment in the power grid.
Harm of Harmonics on Power Supply Equipment
Power transformer and generator loss increase, resulting in overheating damage；
Cable overheating, insulation aging；
Power capacitor dielectric loss increases, overheating；
Neutral current increases, overheating.

Harm of Harmonics on Electrical Equipment
Sensitive load is disturbed, PLC error, crash;
The protection device malfunctions and the switch trips incorrectly;
The servo motor generates pulsation, AC motor generates vibration, and noise increases;
Line-conducted electromagnetic interference, digital transmission failure, communication interruption;
Lighting and display flicker.
Harm of Harmonic to the Power Grid
The quality of the power grid deteriorates, the waveform distortion increases, and the frequency changes;
Excessive consumption of reactive power and current RMS in the grid;
The burden on the power grid is increased and the available capacity is reduced.
Benefits of Dynamic Reactive and Harmonic Control Equipment
1 By improving the power factor, the total current in the line and the electrical components in the power supply system are reduced, such as transformers, electrical equipment, wires, etc., thus reducing investment costs and reducing the loss of its own electrical energy.
2 Good power factor value, reducing voltage loss in the power supply system, which makes the load voltage more stable and improves the quality of the power.
3 It can increase the margin of the system and tap the potential of the power generation and supply equipment. If the power factor of the system is low, the power factor can be increased and the capacity of the load can be increased after the capacitor is installed under the condition that the capacity of the existing equipment is constant.
For example, when increasing the power factor of a 1000KVA transformer from 0.8 to 0.98:
Before compensation：1000×0.8=800KW
After compensation：1000×0.98=980KW
For the same 1000KVA transformer, after the power factor is changed, it can bear an extra load of 180KW.
Reduction of user’s electricity bills; discount of electricity fee due to reduction in loss of each component and power factor increase.
At present, the classification of such equipment in China is as the following:
Contactor Type
The basic principle of the traditional harmonic control device is harmonic bypass. It mainly consists of passive components such as capacitive reactance. As a low-cost compensation scheme, it can only compensate for the reactive power of a relatively stable load. For impact loads, it cannot meet its fast response requirements, nor can it filter out the harmonics generated by 6-pulse devices. When the inrush current is relatively large, it is easy to damage the contactor and cause injury to personnel.CX-APF series active power filter device is jointly designed and developed by Changxiang Electric and North China Electric Power University. It fully complies with China’s GB standard. It can perfectly filter the harmonics in the power grid and is not affected by the grid operation structure.
The CX-APF adopts a precision modular design. The capacity of a single module is 50A, 75A, or 100A. According to the harmonic current content of the site, multiple modules can be connected in parallel for expansion. The maximum capacity is 600A. And the cabinet can be combined to further expand capacity. Flexible configuration, small size and portable installation provide great convenience for user design and installation.

Working Principle

The CX active power filter detects the load current through the current transformer, and extracts the harmonic component in the load current through the internal DSP calculation, and then sends it to the internal IGBT through the PWM signal to control the inverter to generate a harmonic current equal-sized, opposite-direction with load harmonic currents to be injected into the grid for filtering purposes.
Technical Features
Excellent Filtering Effect
1. The harmonic control efficiency is up to 95%, the harmonic control range is 2-50 times, and the single harmonic filtering depth is up to 100%.
2. With subversive control mode in the industry, switching frequency up to 20KHZ, and the filter loss is minimized, which does not affect the grid system impedance. The output waveform is accurate, and will not affect other equipment.
3. Stronger tolerance to input voltage fluctuations and distortion.
4. The machine is versatile, which can simultaneously control harmonics, reactive power and three-phase unbalance.
5. Friendly Chinese operation interface
6 A variety of protection functions: over-current, over-voltage, under-voltage, over-temperature, circuit failure detection and other protection functions.
7 Advanced modular structure, with small size and high capacity ratio; up to 6 modules can be installed in a single cabinet, or embedded in a third-party cabinet.
Model Instruction

TZ-APF/3L-400V-50A/B

Notes:
1 Series code: TZ series
2 Wiring method: 3L means three-phase three-wire system, 4L means three-phase four-wire system
3 Rated voltage: 400V/690V
4 Rated current: 50~3600A
5 Installation form: A: wall-mounted, B: superimposed, C: cabinet

Controllable Thyristor Dynamic Compensation Type
The dynamic filtering and reactive power compensation device has flexible and effective configuration and fast response speed. It can not only dynamically filter out harmonics and compensate reactive power, but also solve power quality problems such as three-phase unbalance, flicker and voltage fluctuation. So it is economical grid management equipment.
Model Instruction
CX-TSF/3L-400V-200KVAR

Notes:
1 Series code: CX series
2 Wiring method: 3L means three-phase three-wire system, 4L means three-phase four-wire system
3 Rated voltage: 400V/690V
4 Installation capacity: 200~3500KVAR