Independent System Operators (ISO) constantly face the challenge of assessing the impact of facility additions to the power grid. They normally require a system impact study for any proposed interconnection of a large generating plant or transmission project. The purpose of this analytical study is to determine the potential adverse impacts of the interconnection of transmission facilities to a power system and whether it would cause any of the following:
- Post-contingency thermal overloading on transmission lines and transformers,
- Voltage criteria violations on substations,
- Negative impact on the dynamic response of power system facilities,
- Degradation on the transfer limit of transmission interfaces,
- Increase in substation short circuit current that could possibly exceed the fault duty of existing circuit breakers.
The system impact study determines the impact of the proposed project by comparing simulation results of the case with the project in service against the case without the project. If adverse impacts were to be found, appropriate solutions to mitigate the violations would be required, except for the extreme contingency assessment which is performed for information purposes on issues such as avoidance of widespread load interruptions, uncontrolled cascading, and system blackouts among others.