ZSI Application for Reducing the Energy Incident of Arc Flash in a Distribution System

The safety of workers and equipment in the power system can be done using a safety system. This system consists of several components that work based on certain algorithms that will work if the system experiences interference. One major disturbance that can harm the system and the workers in it is the arc of fire. This disturbance begins with a short circuit that has enough energy to produce arcs of fire and even to an explosion. Relay equipment and circuit breakers can be used to protect the system. While humans can use Personal Protective Equipment (PPE) as a safety. PPE is determined based on the energy level of the incident from the arc. One effort to reduce this energy is to reduce the time of occurrence of arcs. The time of the incident is very closely related to relay work time. Relay working time determines the circuit breaker (CB) termination when a short circuit occurs. The shorter the relay's working time, the arc will also be shorter. Improvising the relay work time must pay attention to coordination between relays so that no trip errors occur. For this reason, the Zone Selective Interlocking (ZSI) method will be used to maximize work time and relay coordination by dividing the system into several protection zones. This study takes the case of a 20 kV distribution system. A distribution system with a large amount of load will increase the potential for interference. Simulation results show that ZSI can reduce the time the arc arises and does not interfere with relay coordination.