Philosophy of Relay Protection

The philosophy of protective relaying is to provide protection or isolation to an area of the electric system that has a disturbance as quickly as possible to prevent damage to the power system. Along with this, you want to leave as much of the power grid in tact to continue service to the customers. Protective relaying helps protect equipment from damage due to abnormal operating conditions. Protective relaying does not prevent abnormal operating conditions but limits the amount of time these conditions can exist. Relaying can detect all kinds of abnormal operating conditions such as over-current, over-voltage, and under-voltage. There are things you need to consider when deciding on what type of system protection you are going to use. The things you need to consider are reliability, selectivity, speed, simplicity, and economics. Reliability consists of assurance that the protection system that is in place will operate correctly. Selectivity consists of ensuring that the amount of the service area disturbed is kept to a minimum. The speed of the system must minimize the duration of the fault and also minimize the amount of damage that may occur to the system. The use of the minimal amount of equipment to achieve the type of protection you want is also important. This will keep things less complicated and also relates to the last thing to consider in a protection system which is cost. You want the maximum amount of protection but at a minimal cost. All of these factors help build a cost effective and reliable protection system that will protect our infrastructure. Protective relaying is a very important component of the electrical system. It protects very important and expensive pieces of equipment such as transformers from damage due to faults and other abnormal conditions that may exist on the power grid. More importantly it keeps us with power to our homes at an affordable price. Relaying, while initial costs are high, save utilities money which they can