Operation and Features of Dynamic Voltage Restoration:
– Dynamic voltage restoration injects a voltage to restore load side voltage.
– Devices for dynamic voltage restoration use gate turn off thyristors (GTO) in a PWM inverter structure.
– DVR can generate or absorb independently controllable real and reactive power at the load side.
– The source of injected voltage is the commutation process for reactive power demand.
– The amplitude and phase angle of injected voltages are variable, allowing control of real and reactive power exchange.
Similar Devices and Technologies:
– DVRs and low voltage ride-through (LVRT) systems in wind turbine generators use a technically similar approach.
– Dynamic response characteristics of DVRs and LVRT-mitigated turbines are similar.
– Conduction losses in both devices are minimized using IGCT technology in the inverters.
Applications of Dynamic Voltage Restoration:
– DVR systems can inject up to 50% of nominal voltage for a short time.
– DVRs can mitigate damaging effects of voltage swells, unbalance, and waveform distortions.
– Most voltage sags are much less than 50%, so this is not typically an issue.
Drawbacks and Considerations for Using DVRs:
– DVRs are not suitable for systems with prolonged reactive power deficiencies or vulnerable to voltage collapse.
– Applying DVRs requires considering the nature of the load and the transmission system’s voltage-response.
– Local fast reactive supply sources may be necessary to protect the system from voltage collapse.
Comparison of SSSC and DVR for Series Voltage Sag Compensation:
– SSSC and DVR are utilized for series voltage sag compensation.
– SSSC injects a balanced voltage in series with the transmission line, while DVR compensates for unbalance in supply voltage.
– DVRs are usually installed on critical feeders with DC energy storage for active power supply and internal reactive power generation.
Related Concepts:
– Electric power quality
– Voltage sag
– Static synchronous series compensator (SSSC)
– SSSC Source: https://en.wikipedia.org/wiki/Dynamic_voltage_restoration
This article may be too technical for most readers to understand. (July 2017) |
Dynamic voltage restoration (DVR) is a method of overcoming voltage sags and swells that occur in electrical power distribution. These are a problem because spikes consume power and sags reduce efficiency of some devices. DVR saves energy through voltage injections that can affect the phase and wave-shape of the power being supplied.
Devices used for DVR include static var devices, which are series compensation devices that use voltage source converters (VSC). The first such system in North America was installed in 1996 - a 12.47 kV system located in Anderson, South Carolina.
