Background
Within an industrial electricity grid, the protection of equipment and people requires a protection plan to be put in place, based on a designation of the settings for the protection equipment, respecting specific protection coordination principles. That is to say, each protection device must be able to trip by the faults assigned to it and not be inadvertently tripped with the appearance of other faults.
Requirement
Internal modifications to an HV or LV grid or to the electrical connection point (short-circuit power), can render the initial settings of the protection devices obsolete and thus their ability to eliminate short-circuit currents at the correct level has to be reviewed.
Service principle
To provide this type of service, Capsim initially performs calculations of the fault currents at all concerned points on the grid. The objective is to identify the minimum and maximum fault current values currents to be eliminated by protective devices present.
The next stage consists of analyzing the protection plan or defining a new one: which protection devices must respond in the event of a fault and under defined criteria.
The settings and protection coordination analysis stage involves constructing current-time curves allowing the protection coordination to be verified.
These studies are performed by CAPSIM via software such as ETAP, PowerFactory, Cyme, PSS-E, EDSA, CANECO HT and BT, etc depending on the context and client requirements.
Results
Depending on the outcome of the analysis of the existing system, Capsim will be able to recommend :
- Validating the protection plan in its current state
- Validating the protection plan by recommending the modification of some settings of the protection devices (settings file)
- Review and modify the protection plan by defining a new protection strategy for the site (generally practised on sites wishing to change the technology of their protection devices: e.g. changing from analogue to digital)
Protection coordination curve (distribution grid of a methane terminal)
