Real-time control-type dynamic voltage regulator (DVR)

Fast and real-time correction of voltage sag/swell to ensure voltage stability Voltage sag problem solution

With the rapid growth of modern power industry and the significant changes in the electrical load structure in the system, the dependence of social production and officing on electronic equipment is growing rapidly, in which voltage sag becomes a major problem. According to EPRI's authoritative data, more than 92% of power quality events are related to voltage sag and swell, and other power quality events account for less than 8%. Voltage sag has been identified by many international research institutions as the most-frequently occurred event in the power system. Therefore, voltage sag (swell) protection for sensitive equipment is particularly important.


  • Industry site design
    The input or output of KLD-DVR system can be configured accordingly in different power supply situations to meet the power supply requirements on all occasions.
  • Powerful scalability
    With modular superposition design, the capacity can be increased or decreased to meet different demands for capacity.
  • Better characteristics on control of voltage sag
    KLD-DVR has automatic voltage regulation function, and can control single phase, two phase, three phase drop to 0%. The equipment output voltage is stable.
  • Excellent rectification performance, and no harmonic injection
    The advanced IGBT green rectification and multiple protection technologies support absolute reliability of the device, prevent harmonic injection pollution, and improve power utilization.
  • Online hot plugging
    Each part of module has realized online hot plug operation, which provides guarantee for product upgrade or maintenance.
  • Product interactivity
    Real-time monitoring can be achieved through communication or network, and assist users in dealing with system crisis quickly and flexibly.

Product Advantages

  • The core processing chip uses 32-bit digital signal processor to achieve high precision, high speed and high real-time control.
  • Small size, high efficiency, and green and environmentally friendly
  • Inverter plug-in redundant design with fault bypass and high reliability
  • Three-level inverters used to improve the working efficiency of whole machine, reduce losses and save power.
  • Enable control of voltage sag and swell
  • DSP intelligent monitoring, high-speed detection and calculation to ensure accurate and effective detection and compensation control
  • Intelligent monitoring function, flexible device operation and control, operating parameters and working status at a glance, and automatic fault diagnosis
  • Scalable communication interface, monitored by PC
  • Standard modular design is adopted. Power circuit and control circuit are in module or component (plug-in) structure, and same modules can be interchanged. Thus, reliability and maintainability in use are improved.
  • Inverter only intervenes when voltage sag occurs, improving operating life and reliability
  • Energy storage components use super capacitors, charging and discharging times up to 1 million times, not required to replace
  • Routine maintenance-free

Switching-in method

The KLD-DVR is connected between the grid and the load. The maintenance bypass switch is optional. When the system fails, the maintenance machinery bypass is disconnected to check and repair the system. The rectifier unit is enhanced-type accessory that can be replenished with energy while the KLD-DVR is operating, enabling KLD-DVR compensation to last longer. If the grid voltage is cut off, the compensation duration can only be extended by increasing the capacity of supercapacitor.

Technical Parameters

Rated AC input line voltage 208V-480V (other voltage level can be customized)
Input voltage scope -15%-+15%
Grid frequency range 50Hz/60Hz±5Hz
Wiring method Three-phase three-wire/three-phase four-wire
Multi-machine parallel connection Support multi-module parallel
Working efficiency >99%
Compensation capacity Standard model 0~100% residual voltage compensation to 100% for 1s (enhanced type is customizable according to customer requirements)
Output frequency 50±0.01Hz or 60±0.01Hz
Harmonic of voltage ≤3%
Voltage unbalance (negative sequence / positive sequence) <3% under 100% unbalanced load
Overload capacity 200%
Performance indicators
Voltage sag compensation Available
Voltage swell compensation Available
Maintenance machinery bypass Optional
Rapid response time <10us
Full response time <1ms
Noise ≤ 60db (100% load)
Heat dissipation mode Intelligent air cooling
Protection function Short circuit protection, DC bus undervoltage/overvoltage protection, power semiconductor fault protection, overload protection, etc.
Interface module
Display Touch large screen display is adopted.
Communication RS232 or RS422, RS485, SNMP Network card(optional)
Environmental for Use
Ambient temperature -10℃~+50℃
Environmental Humidity Maximum 95%RH (non-condensing)
Storage temperature -25℃~55℃
Altitude <1500m, the power is reduced by 1% for every 100m above 1500m
Protection class IP20 (customizable for higher classes)

Size and Model

KLD-DVR dynamic voltage regulator selection

KLD-DVR standard three-phase three-wire system selection

Commonly Used Model Capacity (KVA) System voltage (V) Type Protection class
KLD-DVR30-3L-400V 30 400 Standard Type NEMA1(IP20)
KLD-DVR60-3L-400V 60 400 Standard Type NEMA1(IP20)
KLD-DVR100-3L-400V 100 400 Standard Type NEMA1(IP20)
KLD-DVR120-3L-400V 120 400 Standard Type NEMA1(IP20)
KLD-DVR150-3L-400V 150 400 Standard Type NEMA1(IP20)
KLD-DVR300-3L-400V 300 400 Standard Type NEMA1(IP20)

KLD-DVR standard three-phase four-wire system selection

Commonly Used Model Capacity (KVA) System voltage (V) Type Protection class
KLD-DVR30-4L-400V 30 400 Standard Type NEMA1(IP20)
KLD-DVR60-4L-400V 60 400 Standard Type NEMA1(IP20)
KLD-DVR100-4L-400V 100 400 Standard Type NEMA1(IP20)
KLD-DVR120-4L-400V 120 400 Standard Type NEMA1(IP20)
KLD-DVR150-4L-400V 150 400 Standard Type NEMA1(IP20)
KLD-DVR300-4L-400V 300 400 Standard Type NEMA1(IP20)

KLD-DVR-A enhanced model three-phase three-wire system selection

Commonly Used Model Capacity (KVA) System voltage (V) Type Protection class
KLD-DVR30-3L-400V-A 30 400 Enhanced NEMA1(IP20)
KLD-DVR60-3L-400V-A 60 400 Enhanced NEMA1(IP20)
KLD-DVR100-3L-400V-A 100 400 Enhanced NEMA1(IP20)
KLD-DVR120-3L-400V-A 120 400 Enhanced NEMA1(IP20)
KLD-DVR150-3L-400V-A 150 400 Enhanced NEMA1(IP20)
KLD-DVR300-3L-400V-A 300 400 Enhanced NEMA1(IP20)

KLD-DVR-A enhanced model three-phase four-wire system selection

Commonly Used Model Capacity (KVA) System voltage (V) Type Protection class
KLD-DVR30-4L-400V-A 30 400 Enhanced NEMA1(IP20)
KLD-DVR60-4L-400V-A 60 400 Enhanced NEMA1(IP20)
KLD-DVR100-4L-400V-A 100 400 Enhanced NEMA1(IP20)
KLD-DVR120-4L-400V-A 120 400 Enhanced NEMA1(IP20)
KLD-DVR150-4L-400V-A 150 400 Enhanced NEMA1(IP20)
KLD-DVR300-4L-400V-A 300 400 Enhanced NEMA1(IP20)