The dynamic voltage restorer (DVR) is used to regulate the voltage at the load terminals from various power quality problems like sag, swell, harmonics, unbalance etc., in supply voltage. This paper presents modelling aspects of several types of Dynamic Voltage Restorer (DVR) working against various voltage sags by simulation in PSCAD/EMTDC. The reference signal for the series connected DVR is ...

This paper presents dynamic simulation and control of stand-alone doubly fed induction generator (DFIG) loaded with 3-phase motors (IMs). The study reveals that direct on-line starting large IMs causes a voltage sag across the terminals as current drawn reaches up to 8-9 times rated load current. Traditionally, this problem has tackled by oversizing or employment special starters, under pretext...

Any power quality disturbance waveform can be seen as superimposition of various oscillating modes. It becomes necessary to separate different components of single frequency or narrow band of frequencies from a non stationary signal to identify the causes which contribute to power quality disturbances. In this paper a method is proposed to detect and classify voltage sag causes based on Empiric...

This paper describes the causes of voltage sags in affecting process industries, their impacts on equipment operation, and possible solutions. The definition proposed focuses on system faults as the major cause of voltage sags. The sensitivity of different types of process industry equipment; including adjustable speed drive controls, programmable logic controllers, and motor contactors; is ana...

Any power quality disturbance waveform can be seen as superimposition of various oscillating modes. It becomes necessary to separate different components of single frequency or narrow band of frequencies from a non stationary signal to identify the causes which contribute to power quality disturbances. In this paper a method is proposed to detect and classify voltage sag causes based on Empiric...

Unified power quality conditioners (UPQCs) allow the mitigation of voltage and current disturbances that could affect sensitive electrical loads while compensating the load reactive power. This paper deals with unified power quality conditioner (UPQC), which aims at the integration of Series-active and shunt-active power filters. The main purpose of a UPQC is to compensate for voltage Imbalance...

This paper presents voltage control scheme by using directly voltage-controlled distributedenergy resource units (VC-DERs) of an islanded microgrid to provide overcurrent,voltage sag and harmonics protection. The overcurrent protection scheme detects the fault, limits the output current magnitude of the DER unit, and restores the microgrid to its normal operatingconditions subsequent to fault c...