Yasir Arafat

Low voltage DC distribution system compared with 230 V AC

In this work low voltage DC distribution systems for a home are investigated by evaluating the advantages and disadvantages to 230V systems. The aim of the work is to connect the systems with local generation such as solar cell, micro turbine and energy storages at the end user level. Data obtained from measurements of power consumption for different household appliances such as refrigerator, microwave oven, rice cooker, dish washer etc. have been used to evaluate the systems. The performance of the 230V AC system and the proposed low voltage DC system is analyzed by considering factors such as losses in the wire, internal loss of the device itself, investment cost for new wiring, energy consumption cost

Remote switching of multiple smart meters and steps to check the effect on the grid's power quality

The traditional electrical grid is transitioning into the Smart Grid (SG) and the introduction of Smart Meter (SM) is a first stage towards Smart Grid. The SM can offer new functionalities such as remote reading, automatic event reporting and the possibility of remote switching by the Distribution System Operator (DSO). The DSO can send remote signal to the breaker of the SM to disconnect or connect customers. This could be used when customers are moving or do not have a contract. DSO is currently applying this technique regularly for customers but one by one which do not affect the grids power quality remarkably. But this technique has never been applied for multiple customers at a time in a single neighborhood and the possible effect on the grids power quality is still unknown. This condition is studied in this paper through test scenarios which have already been planned to test. This paper presents necessary steps of remote SM switching for a large number of customers. Power quality standards and steps for measuring power quality during the tests are outlined. Possible risks of the test as well as the probability of occurring risk and also the consequences of those risks are studied in this paper.

An efficient appliance for low voltage DC house

Kitchen appliances consume large amount of energy in residential houses. By using efficient appliances energy losses can be reduced. Most of the household appliances use DC internally except some appliances such as stove, refrigerator, dishwasher and microwave oven. The refrigerator and stove is one of the high power consuming kitchen appliances and it consumes large amount of energy. This work investigated on energy efficient home appliance design to run on low DC voltage and the purpose is to reduce energy consumption and losses. A combined refrigerator stove unit is designed to run on low voltage DC. The system is simulated with Matlab / Simulink and finally a prototype is built to analyze the performance.

Field test on multiple Smart Meter switching to study the effect on power quality at customers level

Smart Meters (SMs) are undergoing an increasing deployment all over the world and have been introduced to several regions. The SMs generally have remotely accessible breakers which offer remote switching functionalities to the Distribution System Operators (DSOs). The DSOs have the possibility of using this unique functionality of SMs for various future applications, e.g., switching some loads during peak loads crisis or outage management during natural disasters. Under these conditions, the DSO can disconnect selected customers by using SM switching while continuing power supply to risk customers and emergency service providers. During multiple SM switching, the power quality (PQ) of the connected loads might be affected. This paper presents results on the impact of multiple SM switching at customer level. Data are used from a field test on multiple SM switching from a DSO in Sweden. The number of customers in this test was higher compared to the previous two tests of the work. Moreover, all customers in the selected test area were not switched in this test. Almost half of the customers in the test area were disconnected remotely using SMs while the other half of the customers remained connected with power supply to investigate the impact of SMs switching in a different way. This work observed some transient events during the SMs switching. Voltage quality was stable during the test except some flickering effects beyond the limit.