Experimental study on flicker emissions by photovoltaic systems on highly cloudy region: A case study in Malaysia

• The power output of photovoltaic system is greatly intermittent in Malaysia.
• The high intermittency of PV power output leads to the generation of severe flickers.
• Some of the flickers can be well above the statutory limits.
• The severity of flickers grows as the PV capacity is increased.
• The load controller is a cheap and effective method for mitigating flickers.

Photovoltaic (PV) systems are the most promising renewable energy sources in Malaysia because of its location being around the equatorial region where sunlight is available throughout the year. However, the country is warm and surrounded by the South China Sea and Malacca Straits. A large amount of clouds is created and passed over the region. The impacts of the passing clouds on the PV power outputs and voltage magnitude have to be studied thoroughly. Therefore, an experimental low-voltage network integrated with a PV system is set up. The experimental results show that the passing clouds result in the frequent and rapid fluctuations of PV power outputs, hence producing a large amount of flickers to the distribution networks. Some of the flickers are actually greater than the statutory limits. To mitigate this power quality issue, a dynamic load controller is proposed to be the solution because its components are cheap. The load controller is made of a number of 200 W power resistors and solid-state relays. A central controller switches the resistors on and off very rapidly based on the fluctuations of the network voltage. The experimental results show that the dynamic load controller is able to reduce the flickers effectively on the distribution networks. The studies and solution presented in this paper are very valuable to different parties, such as the government, policy makers, utility companies and owners of the PV systems, in order to ensure an effective growth of the PV systems without compromising the quality of electricity supply to the customers.