VQC Series Integrated Control Device of Substation Voltage & Reactive Power

Introduction

VQC series microprocessor-based integrated control device of voltage & reactive power is suitable for 35-500kV substation, and can simultaneously control 1-3 loaded transformers with tap-changer and 34 group parallel operation capacitors. It can recognize and adapt the change of master transformer operation mode automatically. Perfect blocking and protecting function, friendly MMI and powerful recording capability are employed. It can be coordinated with all kinds of supervisor system, and the device is stable and reliable.

Features

• The device can track the complexion change of substation operation, recognize the operation mode of more master transformers and capacitors automatically and confirm the control strategy automatically.
• Employing modularized structure design, it not only can be used independently but also can be coordinated with all kinds of substation supervisory system.
• It can perform remote or local control to make the device in control state or supervisory state.
• The control mode of device is flexible, which can realize its regulation and control not only according to the voltage and reactive power, but also according to the voltage and power factor.
• The safety constraint of device is reliable, and various protection methods can make sure that the controlled equipment is safe.
• LCD, keyboard operation, friendly MMI, which make the device easy to use.

Technical Parameters

• Measurement error of voltage and current <0.2%
• Measurement error of active power and reactive power <0.5%
• Measurement error of power factor <0.01%
• MTBF >30,000 H
• The time limit between tap-up and tap-down operations of master transformer
  >300 Sec
• The time limit between switch-on and switch-off operations of capacitor
  >120 Sec
• Blocking function
  1. Loaded tap-changer transformer:
  Master transformer slide tap (sending out urgent stop signal, at the same time latching)
  Master transformer reject action
  The tap setting is different when the master transformers parallel in operation
  Master transformer abnormal (including pressure abnormal and gas action etc)
  Protecting action
  Neutral point switch not grounding
  Master transformer breaker double position error
  Busbar connection breaker double position error
  Busbar voltage abnormal
  2. Capacitor group:
  Capacitor abnormal switch-on and switch-off operation
  Capacitor reject action
  Capacitor switch abnormal
  Protecting action
  Control loop separation
  Capacitor switch double position error
  Busbar connection switch double position error
  Busbar voltage abnormal
• Regulative safety constraint function
  Some of the following parameters can be adjusted manually. After the operation parameters of the device meet these settings, the device can generate normal adjusting command.
  1. Loaded tap-changer transformer:
  Master transformer overload hours
  The time limit between tap-up and tap-down operations of master transformer
  Switch-on and switch-off operation times of master transformer in one day
  2. Capacitor group:
  The time limit between switch-on and switch-off operations of capacitor
  Switch-on and switch-off operation times of capacitor in one day
• Voltage priority function
  When the tap-changer of loaded transformer is regulated to the top position and the system voltage is still under the minimum voltage, at this time no matter the reactive power is reasonable, the capacitor will be switched-on by force to increase the voltage. When the tap-changer of loaded transformer is regulated to the bottommost position and the system voltage is still over the maximum voltage, the capacitor will be switched-off by force to decrease the system voltage.

Engineering Application

It has been widely used in substations.