Abstract:
Blackouts with disastrous effects have occurred all over the world including Bangladesh in last few years. The inefficient design of current load shedding techniques is one of the primary causes of the widespread effects of these blackouts. But research into recent blackout occurrences shows that voltage collapse and associated problems are equally crucial to preserving the integrity of power networks. Therefore, when taking preventive measures against blackouts, it is imperative to take both frequency and voltage into account. This necessitates a review of the emergency mechanisms in place to prevent blackouts.
Achieving a sustainable and ecologically friendly energy mix depends on integrating renewable energy sources into the traditional power grid. Solar, wind, and hydroelectric power are examples of renewable energy sources that can produce clean, plentiful energy without consuming natural resources or adding to greenhouse gas emissions. By reducing reliance on fossil fuels and diversifying energy sources, the incorporation of renewable energy resources can improve energy security. Given that renewable energy is frequently locally accessible and may be used, this lessens vulnerability to price changes and supply disruptions.
Traditional load shedding approaches do not incorporate any asynchronous renewable source such as solar photovoltaic (PV). Notably, utility scale PV plants may include Battery Energy Storage System (BESS) to provide supplementary frequency support. In this research an adaptive load shedding methodology is introduced which helps to improve overall blackout protection for renewable integrated power systems. The methodology takes care of frequency and voltage stability in response of combinational disturbances of electric power system. The methodology involves measuring the power mismatch and relative disturbance magnitude with taking advantage from load damping factor. At the same time, it decides the amount of load to be shed from each bus using the voltage and frequency sensitivities combined with the additional inertia support from BESS.
The proposed load shedding methodology is scripted in python language and implemented on New England test system (IEEE 39 Bus) to execute in ‘Digsilent PowerFactory’ environment for all illustrative case studies. The scheme is tested on IEEE 39 bus with python scripted simulation. There are four scenarios considering 250 MW, 500 MW and 1000 MW injection of PV based power generation sources with conventional generation loss of 800 MW and 1000 MW. The threshold frequency is considered 49.10 Hz. The total amount of Battery Energy Storage System is 300 MW. For each case, it can be observed that the scheme successfully maintains the system frequency above 49.10 Hz with a minimal amount of load shedding. Hence, it can be stated that the proposed methodology successfully maintains frequency stability for a modern power system with large-scale PV generation through adaptive feeder selection for load shedding.