Enhancing the Micro-Grid reliability in industrial distribution feeders by generating bus splitting model

Abstract

This thesis aims to explore the stability and control of an Industrial Micro-Grid (IMG) system engaged to provide uninterrupted and high-quality power to around 165 export-oriented industries in Chattogram Export Processing Zone (CEPZ) and 70 similar industries in Karnaphuli Export Processing Zone (KEPZ) located in Chattogram, Bangladesh. The Industrial Micro-Grid model consists of 5 (five) natural gas (NG) fired IC Engine based Generating Sets (GS), each having a capacity of 8.73 MW and 3 (three) others of 9.34 MW individual capacity along with a span of around 80 running KM mixed mode (O/H & U/G) 11 KV distribution network with 3 (three) 33 KV regional national grid connectivity all together. These generators could be operated in either island or grid mode to supply independently power to 15 industrial distribution 11KV feeders of CEPZ and 08 identical feeders of KEPZ having capacity ranging from 2.5 to 5.2 MW of load in each. This entire IMG is mostly dependable on a dedicated 72 MW IC engine based natural gas fired power plant to meet its most of the energy demands. The uninterrupted and reliable power supply is crucial for the operation of export-oriented industries within CEPZ and KEPZ, which collectively demand a maximum of 100 MW of which 72 MW is made available from its internal power generating source and additional 28 MW is sourced from the regional national grid of electricity. Despite the constant demand for uninterrupted power, frequent tripping of this IMG due to various faults mainly originating from consumer ends has posed a significant challenge for its trusted reliability. To mitigate this issue within a tolerable limit, a tactful unique solution called "Generating Bus Splitting (GBS),” was conceived which involves the proposal of disintegrating & relocating of one master feeder from its Central Generation Bus (CGB) to rationally distribute fault burden concentration. This modification also offers several advantages, including grid shifting loss reduction, improved grid dispatch, reduced total blackout risks of the entire IMG, and enhanced emergency power interruption handling capabilities.