Modified methods for voltage-sag source detection using transient periods

A novel voltage sag state estimation method based on complex network analysis

Integrated control algorithm for fast and accurate detection of the voltage sag with low voltage ride-through (LVRT) enhancement for doubly-fed induction generator (DFIG) based wind turbines

In today’s power system, power quality is a critical topic having several impacts on customers and utilities. In the current electric power system, the integration of renewable energy sources, smart grid technologies, and significant usage of power electronics equipment has generated a slew of issues. The sensitive equipment might be damaged by harmonics, voltage sag, and swell. These devices are vulnerable to Interference with other elements of the system resulting in input voltage changes. As a result, in the contemporary period, Power quality is becoming more important as the number of sensitive and costly electronic devices grows. To overcome the challenges of non-standard voltage, the Dynamic Voltage restorer (DVR) device has been extensively utilized to keep the load voltage stable. To have a dynamic and fast response of the DVR a modified instantaneous reactive power (PQ) theory is proposed to control DVR under extreme transient voltage circumstances. The proposed technique is based on the extraction of the positive sequence component of grid voltage and the negative sequence component of load current for generating a voltage reference signal. The power system network with the proposed PQ control scheme is investigated and assessed under various scenarios to compensate for severe balanced, unbalanced (voltage sags and swells), and load change. MATLAB/Simulink is used to verify the mathematical models of the conventional PQ and proposed PQ control system for DVR. The complete system is implemented experimentally using a dSPACE 1104 based laboratory system to validate the presented control scheme. The simulation and experimental results are correlated, demonstrating the efficacy of the suggested modified PQ control technique.

https://ieeexplore.ieee.org/ielx7/6287639/6514899/09804697.pdf

Improved instantaneous reactive power (PQ) Theory Based control of DVR for Compensating Extreme sag and swell

Nowadays, power quality under the excessive implementation of power electronics devices is quite challenging issue. The compensation of non-sinusoidal; reactive and harmonic; components is the main role for power quality devices which highly depend on the robustness of the control system. Some common control systems are implemented using Synchronous Stationary Frame (DQ) theory. This paper proposes a new version of DQ control technique to control dynamic voltage restorer under severe transient voltage conditions. The power system network with the new DQ control technique is studied and analyzed under different scenarios to compensate for severe balanced and unbalanced voltage sags and swells. This new scheme is based on extraction of positive sequence components to implement the control algorithm. A mathematical model of the dynamic voltage restorer (DVR), hysteresis voltage control, converter controller model, new DQ scheme with complete system equations are carried out and verified using Simulink / MATLAB. The proposed system is validated experimentally using DSpace 1104 based laboratory system. The obtained results of the proposed compensation algorithm are compared with the results obtained from the traditional DQ method. Simulation and experimental results are correlated and show effectiveness of the proposed DQ control scheme.

A New Technique Implemented in Synchronous Reference Frame for DVR Control Under Severe Sag and Swell Conditions

Fast and accurate voltage sag detection algorithm

Voltage sags may affect the accurate operation of several equipment connected to power systems. A typical example is the doubly-fed induction generator (DFIG), which is often employed in wind energy conversion systems (WECSs). Since the stator windings are directly connected to the power grid, the generator becomes very sensitive to such power quality disturbances. In this context, this work proposes a fast and accurate algorithm for the detection of voltage sags based on the aggregate value concept. The algorithm allows detecting both symmetrical and asymmetrical single-phase, two-phase, and three-phase events even when the supply voltage is distorted. Experimental results are presented to demonstrate that this algorithm can be considered as a good option for practical applications. 

Subhash Chandra Parija

Papers

Fast and accurate voltage sag detection algorithm

Fast and accurate voltage sag detection algorithm

Synchronverter-based frequency control technique applied in wind energy conversion systems based on the doubly-fed induction generator