YDK series SPC (Smart Power Quality Correct Device) is a new type of power electronic device that Zhejiang Yide Technology Co., Ltd. optimizes and upgrades based on YDK series SVG, which is dedicated to improving the power quality of distribution area. The device can effectively compensate the three-phase unbalance, quickly adjust the reactive power in two directions, and stabilize the system voltage in real time. It is in complete agreement with the management policy and technical principles of the “low voltage” investigation and management of the State Grid.

Application field

In view of the long power supply radius of the rural power grid and the large load change, the voltage at the end of the power supply is low. This product effectively solves the problem of low voltage at the end of the power distribution, ensures normal power supply, low investment cost, and good compensation effect.

Product parameters

System parameters

Rated voltage rating: 380V/480V

Input phase voltage range: -40%~ +20%

Grid frequency: 50Hz/60Hz (range: 45Hz~63HZ)

Network structure: three-phase three-wire, three-phase four-wire

Circuit topology: three levels

Communication monitoring capability

Monitoring mode: standard WiFi module (web access via mobile phone, iPad, laptop light, to achieve data display and parameter setting)


Display content: real-time operation information such as voltage, current, frequency, power factor, operating temperature, etc.

Communication interface: RS485/CAN/network port


Communication protocol: Modbus protocol / general agreement

Environmental requirements

Operating temperature: -10~45°C


Altitude: <1500m, above 1500m, please derate according to GB/T3859.2, or contact dealer


IP rating: IP44


Earthquake resistance: 8

Performance

Three-phase balance compensation capability: unbalance <5%


Rated current (or maximum unbalance compensation current): 45A (SPC-30); 75A (SPC-50); 150A (SPC-100)


Reactive power compensation range: adjustable from -1 to 1


Reactive power compensation capacity: 30kvar; 50kvar; 75kvar; 100kvar


Reactive power compensation rate: >99%


Response time: <15ms


Protection functions: overvoltage protection, undervoltage protection, short circuit protection, reverse protection of inverter bridge, overcompensation protection, double protection against lightning.


Power distribution function: two-way power distribution with C-level lightning protection

Mechanical properties

Model: YDK-SPC-30; YDK-SPC-50; YDK-SPC-75; YDK-SPC-100


Size: W700*1150


Color: stainless steel color


Weight: 58kg (SPC-30); 72kg (SPC-50); 90kg (SPC-75) 115kg (SPC-100)


Installation method: outdoor floor type / hanging type (H rod, F rod)


Mounting angle: <5 degrees


Product model and size

Working principle

Three-phase unbalance compensation principle

After the YDK-SPC is turned on, the system current is monitored in real time through an external current transformer (CT), and the system current information is sent to the internal controller for processing and analysis to determine whether the system is in an unbalanced state, and at the same time, each time the equilibrium state is calculated The current value of the phase conversion is required, and then the signal is sent to the internal IGBT and its action is driven to shift the unbalanced current from the phase with a large current to the phase with a small current, and finally to the three-phase equilibrium state.

Voltage support principle

YDK-SPC samples the compensation point voltage and transmits the voltage information to the internal DSP to determine whether the compensation point voltage exceeds the set value. When the voltage exceeds the voltage regulation upper line (Umax), the SPC outputs the inductive current and reduces the voltage; Below the voltage regulation down line (Umin), the SPC outputs a capacitive current and boosts the voltage. Finally, the phase voltages are stabilized within the normal range.

Principle of reactive power compensation

After the YDK-SPC is turned on, the load current is monitored in real time through an external current transformer (CT), and the reactive power content of the load current is analyzed by internal DSP calculation, and then the PWM signal generator is controlled to send a control signal to the internal IGBT according to the set value. The inverter generates reactive power compensation current that meets the requirements

Product wiring diagram

The SPC installation location is mainly selected on the low-voltage side of the distribution transformer in the distribution area, that is, between the transformer and the user load.

SPC work site installation method


Installation methods include F-bar, H-bar and outdoor floor-standing

Engineering case

Hunan Fuling

The three-phase unbalanced situation of the distribution stations in Hunan Fuling Rural Power Station, Jizhen, Qiaotou, etc. is serious, which has seriously affected residents and industrial electricity. There are great safety hazards (large transformer noise, severe heat, abnormal noise Wait).

Post-processing effect

Unbalanced benefits:Before the on-site treatment, the three-phase current imbalance is serious, the unbalanced current is about 50A, and the zero line current reaches 44A. After the compensation, the three-phase current is basically balanced, the unbalanced current is about 2A, the neutral current drops to 15%, and the imbalance is determined by 34% down to 1%

Before compensation:

Phase A: 109.23A Phase B: 141.29A


Phase C: 93.07A Phase N: 44.35A

After compensation:

Phase A: 108.67A Phase B: 110.85A


Phase C: 108.93A Phase N: 15.06A

Reactive efficiency：After compensation, the reactive power drops significantly, from 9kVar to 1kVar, and the power factor reaches 1。

To sum up

Completely solve the three-phase unbalance problem of distribution network and greatly reduce the line loss of low-voltage distribution network


Reactive power to achieve local balance and improve the power factor of the distribution network


Improve voltage management in real time, stabilize system voltage, improve distribution quality, and improve power consumption environment


Perfectly solve the problem of transformer overload operation caused by three-phase unbalance, and prolong transformer life