Design and Implementation of Hybrid Active Power Filter (HAPF) for UPS System

Hybrid Active Power Filter (HAPF) is designed and applied for Uninterrupted Power Supply (UPS) System to mitigate harmonic currents in UPS during the power conversion from rectifiers to inverters (AC-DC-AC Converters). Various UPS types and topologies are used for continuous power supply without delay and protection to connected loads. In spite of the fact that UPS is one of the power quality apparatus but it has also drawback of disturbing the power system quality of system by current harmonics and voltage distortion during conversion of power. Passive and EMI Filters could not eliminate harmonics effectively from UPS system therefore it requires modern, rapid filtering method as well combination of Active and Passive Filters. Proposed model of HAPF for UPS System could mitigate current harmonics for optimal power transfer and minimize losses, increase overall efficiency, reliability and life span of equipment. Higher harmonic current and higher voltage distortion leads to greater power loss. In this paper the (d-q) theorem is applied for the identification of harmonic currents. The d-q theorem and calculation creates the signal of reference compensation current and this produced signal of current is tracked by the yield current of the voltage source converter.. Hysteresis based controller for HAPF is applied to create the switching signals to regulate and maintain the voltage source converter output currents. Harmonics and efficiencies are analyzed at different loads and on charging and discharging of batteries of various UPS System in different industries and sectors on the basis of experimental investigation then HAPF is designed and implemented. In simulation results, it is observed that THD reduced from 46 to 10%, the harmonic currents were compensated and eliminated effectively which improved power quality of UPS System. Furthermore, addition of proposed HAPF could save the power up to 15 % which lost due to poor power quality of UPS System

A Review of Energy and Power Planning and Policies of Pakistan

Pakistan is facing multiple challenges for harnessing the indigenous energy resources and devise rational energy policies. The country is believed to have abundant energy resources, however, coping substantial electricity supply gap of over 5000 MW. This paper analyses country’s energy and power planning studies conducted since its independence in 1947 and policies announced so far. It is found that water resources management attained more emphasis in early decades of post-independence rather than energy concerns. The first energy and power planning study was conducted in late 1960s and since then various studies were undertaken to supplement five yearly medium term development plans of government. However, it is pertinent to mention that formal energy and power policies were only announced from 1994 onwards owing to growing electricity demand and progressing industrialization. Beside this, the focus of these policies is not only varied but were conceived without undertaking integrated energy planning using energy modeling tools e.g. MARKAL/TIMES; LEAP, ENPEP BALANCE, MESSAGE and EnergyPLAN. It is despite the fact that these tools are successfully applied globally for devising the energy policies and address the complexities of energy system by assisting effective policy formulation. This study recommends that integrated energy planning using energy modeling tools will be helpful to develop sustainable energy policies in Pakistan to eradicate electricity crises

Wireless Sensor Networks for Developing CountriesFirst International Conference, WSN4DC, Jamshoro, Pakistan, April 24-26, 2013, Revised Selected Papers /

XIV, 121 p. 56 illus.online resource

Multi-criteria analysis of electricity generation scenarios for sustainable energy planning in Pakistan

The now over a decade-long electricity crisis in Pakistan has adversely affected the socio-economic development of the country. This situation is mainly due to a lack of sustainable energy planning and policy formulation. In this context, energy models can be of great help but only a handful of such efforts have been undertaken in Pakistan. Two key shortcomings pertaining to energy models lead to their low utilization in developing countries. First, the models do not effectively make decisions, but rather provide a set of alternatives based on modeling parameters; and secondly, the complexity of these models is often poorly understood by the decision makers. As such, in this study, the Analytical Hierarchy Process (AHP) methodology of Multi-Criteria Decision-Making (MCDM) has been used for the sustainability assessment of energy modeling results for long-term electricity planning. The four scenario alternatives developed in the energy modeling effort, Reference (REF), Renewable Energy Technologies (RET), Clean Coal Maximum (CCM) and Energy Efficiency and Conservation (EEC), have been ranked using the Expert Choice® tool based on the AHP methodology. The AHP decision support framework of this study revealed the EEC scenario as the most favorable electricity generation scenario followed by the REF, RET and CCM scenarios. Besides that, this study proposes policy recommendations to undertake integrated energy modeling and decision analysis for sustainable energy planning in Pakistan