Power quality improvement of distribution power networks using capacitor-less H-bridge inverters for voltage regulation

The proposed Icos⁡ϕ control technique has been applied for power quality improvement using different configurations of system with distribution static compensator (DSTATCOM). Modeling, design and control of DSTATCOM are analysed in detial. Three phase reference current are extracted with this technique. The proposed technique has been used for power factor enhancement, voltage regulation, harmonic suppression and load balancing under dynamic condition with non-linear load. The proposed control is very effective for three different configurations of system with DSTATCOM for power quality improvement. Results for each configuration of system with DSTATCOM are simulated using MATLAB/Simulink sim power tool box. For teaching the power quality course, these can also be helpful.

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An SVC controller for Power Quality Improvement of a Heavily Loaded Grid

Mehran University Research Journal of Engineering and Technology ◽

10.22581/10.22581/muet1982.2002.03 ◽

2020 ◽

Vol 39 (2) ◽

pp. 247-256

Author(s):

Faheem Ali ◽

Muhammad Naeem Arbab ◽

Gulzar Ahmed ◽

Majid Ashraf ◽

Muhammad Sarim

Keyword(s):

Quality Improvement ◽

Power Quality ◽

Power Factor ◽

Distribution System ◽

Reactive Power ◽

Cooling System ◽

Voltage Regulation ◽

Voltage Regulators ◽

Air Cooling ◽

Power Quality Improvement

Pakistan is faced with energy crises from the last two decades. Generation cannot balance the load demands of the electricity consumers. Power delivery systems are generally old-fashioned and overloaded. They are unable to provide consistent and uninterrupted supply to commercial, industrial, and domestic loads. Generally speaking, the Power Systems consist of loads that are inductive and resistive in nature. Heavy machinery, induction motors, and arc furnaces are heavily inductive in nature. Inductive loads when operated in a weak power system results in lagging VARs (Volt Ampere Reactive) and poor voltage regulation, which must be balanced by the same number of leading VARs in order to ensure unity power factor and thus helps in improving the voltage profile. At times the reactive VARs injected may not be sufficient to balance the VARs requires by the system, but still the power factor is improved up to some extent. In hot and humid climatic conditions, air-cooling system and chillers greatly burdens the grids. Such loads require excessive reactive VARs, and if not offered with ample reactive power, causes severe voltage drops in distribution system. To manage low voltages and power-factor, household users use automatic voltage regulators while industries connect capacitor banks. Voltage regulators control output voltage within the required limits at the expense of excessive line current from transformer, which may overburden it. Moreover, with each operation of tap changer, current rises which further intensifies line losses. Static capacitors provide stable voltage but repeated variations in load demands reliable and vigorous voltage regulation. This investigation aims to come up with a power quality improvement scheme which would deliver instantaneous control of power (reactive) with SVC (Static VAR Compensator) thus overcoming the shortcomings of step-wise banks of capacitors and or voltage regulators. Simulation work is carried out in MATLAB/SIMULINK and the results are compliance with IEEE Standards for SVCs. The device can offer steady state as well as dynamic VAR compensation under changing load conditions. Result showed considerable improvement both in terms of response time and power factor. Switching time has been improved to less than 1/10th fraction of a second which in previous simulations was 0.7 seconds approximately. Initial power factor without disturbance and without compensation was recorded to be 0.6 lagging, which after compensation was improved to 0.95 lagging. Similarly, in presence of disturbance without compensation the power factor fluctuated between 0.55 and 0.9 lagging, which after compensation was improved to 0.95 lagging and above throughout the course of operation.

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Star/Hexagon Transformer Based Three-Phase Four-Wire DSTATCOM for Power Quality Improvement

International Journal of Emerging Electric Power Systems ◽

10.2202/1553-779x.1983 ◽

2008 ◽

Vol 9 (6) ◽

Cited By ~ 6

Author(s):

Bhim Singh ◽

Jayaprakash Pychadathil ◽

Dwarkadas Pralhaddas Kothari

Keyword(s):

Quality Improvement ◽

Power Quality ◽

Distribution System ◽

Distribution Systems ◽

Reactive Power ◽

Voltage Regulation ◽

Voltage Source ◽

Voltage Source Converter ◽

Three Phase ◽

Power Quality Improvement

A new topology of DSTATCOM (distribution static compensator) is proposed for power quality improvement in three-phase four-wire distribution systems. A three-leg VSC (Voltage Source Converter) is integrated with a star/hexagon transformer for the compensation of reactive power for voltage regulation or for power factor correction along with load balancing, elimination of harmonics currents and neutral current compensation. The star/hexagon connected transformer provides a path to the zero sequence current in a three-phase four-wire distribution system. In order to optimize the voltage rating of the VSC, the star/hexagon transformer is designed to have a suitable voltage rating for the secondary windings for integrating the three-leg VSC. This transformer connection provides the selection of 'off the shelf' VSC for this application and it also provides isolation for the VSC system. The performance of the proposed DSTATCOM system is validated through simulations using MATLAB software with its Simulink and Power System Block set (PSB) toolboxes.

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Power Quality Improvement in Solar Fed Cascaded Multilevel Inverter With Output Voltage Regulation Techniques

IEEE Access ◽

10.1109/access.2020.3027784 ◽

2020 ◽

Vol 8 ◽

pp. 178360-178371

Author(s):

Albert Alexander Stonier ◽

Srinivasan Murugesan ◽

Ravi Samikannu ◽

Sampath Kumar Venkatachary ◽

S. Senthil Kumar ◽

...

Keyword(s):

Quality Improvement ◽

Power Quality ◽

Output Voltage ◽

Voltage Regulation ◽

Multilevel Inverter ◽

Power Quality Improvement ◽

Cascaded Multilevel Inverter

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An SVC controller for Power Quality Improvement of a Heavily Loaded Grid

Mehran University Research Journal of Engineering and Technology ◽

10.22581/muet1982.2002.03 ◽

2020 ◽

Vol 39 (2) ◽

pp. 247-256

Author(s):

Faheem Ali ◽

Muhammad Naeem Arbab ◽

Gulzar Ahmed ◽

Majid Ashraf ◽

Muhammad Sarim

Keyword(s):

Quality Improvement ◽

Power Quality ◽

Power Factor ◽

Distribution System ◽

Reactive Power ◽

Cooling System ◽

Voltage Regulation ◽

Voltage Regulators ◽

Air Cooling ◽

Power Quality Improvement

Pakistan is faced with energy crises from the last two decades. Generation cannot balance the load demands of the electricity consumers. Power delivery systems are generally old-fashioned and overloaded. They are unable to provide consistent and uninterrupted supply to commercial, industrial, and domestic loads. Generally speaking, the Power Systems consist of loads that are inductive and resistive in nature. Heavy machinery, induction motors, and arc furnaces are heavily inductive in nature. Inductive loads when operated in a weak power system results in lagging VARs (Volt Ampere Reactive) and poor voltage regulation, which must be balanced by the same number of leading VARs in order to ensure unity power factor and thus helps in improving the voltage profile. At times the reactive VARs injected may not be sufficient to balance the VARs requires by the system, but still the power factor is improved up to some extent. In hot and humid climatic conditions, air-cooling system and chillers greatly burdens the grids. Such loads require excessive reactive VARs, and if not offered with ample reactive power, causes severe voltage drops in distribution system. To manage low voltages and power-factor, household users use automatic voltage regulators while industries connect capacitor banks. Voltage regulators control output voltage within the required limits at the expense of excessive line current from transformer, which may overburden it. Moreover, with each operation of tap changer, current rises which further intensifies line losses. Static capacitors provide stable voltage but repeated variations in load demands reliable and vigorous voltage regulation. This investigation aims to come up with a power quality improvement scheme which would deliver instantaneous control of power (reactive) with SVC (Static VAR Compensator) thus overcoming the shortcomings of step-wise banks of capacitors and or voltage regulators. Simulation work is carried out in MATLAB/SIMULINK and the results are compliance with IEEE Standards for SVCs. The device can offer steady state as well as dynamic VAR compensation under changing load conditions. Result showed considerable improvement both in terms of response time and power factor. Switching time has been improved to less than 1/10th fraction of a second which in previous simulations was 0.7 seconds approximately. Initial power factor without disturbance and without compensation was recorded to be 0.6 lagging, which after compensation was improved to 0.95 lagging. Similarly, in presence of disturbance without compensation the power factor fluctuated between 0.55 and 0.9 lagging, which after compensation was improved to 0.95 lagging and above throughout the course of operation.

Download Full-text