Technical Specifications

Key Features

Dongfang Hitachi provides integrated solutions to meet our customer’s needs on power quality control and management. Our solutions include power quality data collection and analysis, system design, equipment selection & configuration, and system monitoring.

Our DHSTATCOM series, with the latest reactive power compensation technology, truly realizes the dynamic reactive power compensation. This electrical control equipment can provide dynamic reactive power support to the power system, filter out the harmonics, suppress voltage fluctuation and flicker, and correct the three phase unbalance.

Adopted direct power control technology to compensate reactive power

Direct power control technology is applied to enable DHSTATCOM to emit or absorb reactive power as commanded. The commanded reactive power can be fixed (given by the grid scheduling for example), and it can also be instantaneous in the dynamic compensation system.

Adopted multiple algorithms to eliminate harmonics up to 13^th order

Applied both Instantaneous and Discrete algorithms, DHSTATCOM series can be used for different load conditions. Its switching frequency is 5kHz, and it can suppress harmonics up to 13^th order.

Adopted compensation control technology to balance three-phase voltages

Compensation control algorithms are applied to correct the unbalance of three-phase voltages. When there is large impedance in the system, the commanded reactive current of each phase is obtained using voltage amplitude closed-loop, and balancing three-phase voltages can be accomplished by controlling each of the three phases.

Adopted closed-loop voltage control technology to suppress voltage fluctuation

Closed-loop voltage control technology is applied in DHSTATCOM series to smooth out system voltage fluctuations caused by grid voltage variation or instantaneous change of the loads. The suppression rate on voltage flicker can reach to 5:1 or even higher.

Fast Response Time

Instantaneous response time is less than 1 ms, while conventional response time of Static Var Compensator (SVC) is greater than 20 ms.

Smaller floor space

No need to use large-capacity capacitors and reactor as energy storage components, the floor space required is 50% or even smaller of SVC’s with the same capacity.

Applications

Long Distance Power Transmission

DHSTATCOM can significantly improve the performance of electric power transmission and distribution systems. One or multiple DHSTATCOMs can be installed at power transmission lines to stabilize voltage, reduce transmission loss, and improve grid stability.

Industrial Applications

The impulse reactive power generated by mills and other symmetrical loads can cause voltage drop and fluctuation. Consequently, the electrical equipment cannot work properly, and productivity is affected. Secondly, the transmission facility of the loads is the major source of high-order harmonic pollution. DHSTATCOM can help to solve these problems, keeping the grid voltage stable, improving the power factor and filtering out the harmonics.

Power Supply System of Electric Locomotives

The mainstream electric locomotives may produce serious pollutions to the grid. These single-phase loads cause problems of three-phase unbalance, low power factor, and negative sequence current. Using DHSTATCOM will tackle these issues, and thus enhance the power supply capacity for locomotive traction and improve the electrical equipment utilization.

Wind Farms

Wind power’s uncertainty and turbine’s operating characteristics lead to output power fluctuation, and cause problems of low grid power factor, voltage deviation and flicker, etc. To solve these problems, dynamic reactive power compensation system is needed when large capacity wind power system connects to the grid. DHSTATCOM will help to increase the power factor and reduce the disturbance to the wind turbine. In addition, the mobility and extensibility of the DHSTATCOM series make it possible to be in sync with wind farm’s expansion.

Solar Plants

The solar power plants operate at constant voltage mode with negative feedback control and low reactive power capacity. Therefore, the voltage collapse could happen when grid voltage or sun irradiation fluctuates. Installing DHSTATCOM can enhance the low voltage tolerance, for reducing the probability of off-grid and achieving improved performance of the solar power generation systems.

Other Applications

Electrical substations, mining sites, chemical plants, and ports etc.