SOURCE:

Faculty: Engineering
Department: Electrical Engineering

CONTRIBUTORS:

Ndubisi, M. A.
Ezechukwu, O. A.

ABSTRACT:

Transmission congestion occurs in a power system when there is insufficient transmission capacity to simultaneously accommodate all requests for transmission service within the network. The modelled 41 Bus 330kV Nigerian power system comprises of 14 generator buses (Egbin is used as the Slack or reference Bus, with 13 other Generators buses), 27 loads buses and 63 Transmission lines, all modelled with data obtained from National Control Centre (NCC) and Transmission Company of Nigeria (TCN) using Power System Analysis Toolbox (PSAT). A load flow simulation of Nigerian 41 Bus 330kV power network (Base case) using Newton Raphson’s iterative method was performed in order to estimate the following unknown variables: generator reactive power, the bus angle, load voltage, line loss and MVA flow. The simulation results show that sixteen voltage profile violations occurred, indicating 39% violations and eleven violated MVA flow transmission lines indicating 15.87% violations hence an unhealthy network. To achieve loss minimization and a healthy network, the output power of the generators were changed through a known optimization technique such as DC optimal power flow. The results reduced the Base case violations to eleven (voltage profile) indicating 26.83% and four (MVA flow) indicating 6.3% violations with the network still unhealthy. In order to get a healthy network, SVC and TCSC were installed separately with the output power of the generators rescheduled. The results obtained could not make the network healthy. In a bid to get a healthy network, combined installation of SVC, TCSC and Generator Rescheduling was also simulated. The simulation results obtained gave a 0% violation on both Bus profile and MVA flow, showing that simultaneous combination of FACTS devices (SVC and TCSC) and generator rescheduling best managed the congestion in the Nigerian Power System.