LSVG-C dynamic filter compensation system

LSVG-C dynamic filter compensation combines dynamic reactive power compensation and static var generator technology (SVG), as well as active power filter technology (APF), provides a series of products, which are capable of fast and effective dynamic reactive compensation against fluctuating loads under various operating conditions, and compensate voltage fluctuation and flicker, unbalanced load, power factor and harmonics, thus obtaining obvious benefits of energy saving while improving power quality effectively.

The dynamic filter compensation system brings together many advanced technologies in the field of power quality control:

Control unit -- the multi-core processor architecture of ARM+DSP+FPGA is used to compute the reactive power and harmonics for compensation of the system in real-time, control the coordination of SVG and SVC branches intelligently, thus achieving the optimal adjustment to power quality indexes of the system;

SVG unit -- a reactive power generating unit with the core of IGBT (Insulated Gate Bipolar Transistor) switch and a full-digital power electronic device, which uses advanced high-frequency switch PWM pulse width modulation and achieves electrical power transformation, with the advantages of fast response speed, successive output current adjustment, high precision compensation, insensitive to grid parameters, and no resonance, etc. It is provided with low-loss high frequency LC filter circuit within the unit, which has good filter effect on harmonics generated by high frequency switch;

SVC unit -- the advanced technology of fast SCR zero-cross switching is adopted to realize zero voltage input, zero current switching, no inrush current during switching and no impact to power grid. The intelligent digital control system tracks the reactive power changes of system load quickly, and realizes instantaneous switching control with the response time of less than 5ms. The soft magnetic vertical winding reactor is used as the connecting reactor, of which, the temperature rise, noise and magnetic leakage are greatly lower than the traditional iron-core reactor, which makes the device operation safer and more reliable.

APF unit -- the active power filter unit with IGBT (Insulated Gate Bipolar Transistor) switch as the core, detects system current in real time, separates the harmonic current successively based on digital fast Fourier transform technique, generates control signals according to the set compensation percentage to drive the IGBT to generate compensation currents of equal magnitude and opposite phase, which offset each other with harmonic components of system current to achieve harmonic filtration effect.

System composition

LSVG device is mainly composed of main switch disconnector QF, current transformer TA, arrester FV, control unit (ECU), active power filter (APF), low-voltage static var generator (SVG) and low-voltage static var compensation (SVC), and the functional units can be freely configured according to user requirements.

The device uses the control unit to control the SVG unit, the SVC unit, and the APF unit, and the target values such as reactive power, voltage, power factor, and harmonic filtration rate can be used as the judgment basis of the switching device to track the load change and dynamic switching quickly. At the same time, the system also has an automatic fault-tolerant operation mechanism, enabling the device to run more safely and effectively.

Performance advantages

■Intelligent control

The controller adopts multi-core processor architecture of ARM+DSP+FPGA and has powerful computing capability, which is very suitable for real-time data acquisition, high-speed parallel computing, remote data communication and dynamic graphic display; the whole set of equipment adopts an intelligent control unit to coordinate control in a unified manner, which not only controls the automatic switching of the SVC unit, but also controls the compensation current output of the SVG unit, and also controls the harmonic current in the APF unit compensation system; adopt the latest full-color display screen with friendly interface, which is simple and convenient for operation; real-time display of various parameters such as operating parameters and operating state, etc., real-time fault record and event record, automatic fault diagnosis; be provided with remote communication interface and can be monitored by PC in real time.

■Flexible compensation

Flexible compensation mode: SVG unit and SVC unit can be configured with various capacities, including common three-phase compensation, single-phase compensation or combination of common three-phase compensation and single-phase compensation, which is tracked automatically and compensated intelligently according to the reactive changes of the system. APF unit can compensate harmonics of different orders and process harmonic current of the system efficiently according to the filtration rate set by the customer;

Flexible installation and application: SVG, SVC and APF unit structure types are both horizontal and vertical, which can be flexibly adapted to various operating conditions and spaces.

■Structural highlights

SVG unit, SVC unit and APF unit all adopt unique modular structure design with compact structure and the unique cooling channel of good heat dissipation effect, achieving standardized production to make installation, wiring and maintenance more simple and convenient.

■Efficient compensation

Full reactive power compensation and system harmonic current compensation.

■Dynamic compensation

Real-time detection of reactive power shortage and harmonic current, dynamic tracking compensation; fast response time, with the complete response time of each functional unit of less than 5ms and the complete response time of the whole set < 20ms.

■Stable and reliable

Standardized process production improves the operational reliability and performance stability of the device; SVG, SVC and APF units are equipped with high quality devices to ensure product performance and life; SVC unit adopts the technology of fast controlled SCR zero-cross switching, which has no oscillation while switching; the internal inductive coils and reactors of SVG, SVC and APF unit adopt advanced soft magnetic technology, which makes the performance more superior and the operation more reliable.

■Complete protection

Complete protection measures including over-current, over-voltage, under-voltage and lack-phase protection, output over-current and over-temperature protection, comprehensive control protection and other functions to ensure the long-term stable operation of the device.

■The system is provided with automatic fault-tolerant operation mechanism

When the system runs automatically in SVC+SVG+APF mode, if SVG fails, it will automatically switch to SVC+APF mode. If part of the branch of SVC fails, it will be removed from the switching sequence and other SVC branch can still switch normally.

■Be provided with restart function after failure recovery

Model description

Technical parameters

Input voltage: rated voltage is 380V, voltage range is 304V~456V, unbalance of input voltage ≤ 5%

Wiring mode: three-phase three-wire or three-phase four-wire

Filter performance: single harmonic filtration rate is up to 90%

Response time: ≤5ms

Electric parameter detection and display: three-phase voltage, three-phase current, active power, reactive power and power factor, etc. of the system

Equipment security: over-voltage/under-voltage protection, over-current protection, over-temperature protection and lack-phase protection of the system, voltage/current harmonic over limit protection, latching alarm and failure information data retention, etc.

Control unit: multi-core processor architecture of RM+DSP+FPGA

Cooling method: intelligent air cooling

Structure type: cabinet structure

Protection class: IP20 (customization is available for special requirements)

Power dissipation: <2%

Reactive compensation precision (the ratio of the absolute value of residual reactive power after compensation to the rated capacity of the device within the rated compensation capacity of the device): ≤1%

Noise: <60dB

Temperature requirements: -15°C〜+40°C, the daily average temperature is not higher than 35°C

Humidity requirements: 15%〜90% (when temperature is 20°C) RH, attention shall be paid to condensation during operation under different temperature and humidity conditions

Altitude: <2000m

Cabinet type: compatible with a variety of cabinet types, customization is available according to customer needs