operation and maintenance of wind power plants

Power system protection is a branch of electrical engineering that deals with the protection of electric power systems from faults by disconnecting faulty parts from the rest of the power grid. 

The goal of the protection scheme is to maintain a stable power system by isolating only the components that are in fault while keeping as much of the network operational as possible. Devices that are used to protect power systems from faults are called protective devices. Protection of the transmission and distribution system fulfills two functions: protection of the plant and protection of the public (including employees). 

At a basic level, protection disconnects equipment that becomes overloaded or shorted to ground. Certain items in substations, such as transformers, may require additional protection based on, among other things, temperature or gas pressure. In a power plant, protective relays are intended to prevent damage to alternators or transformers in the event of abnormal operating conditions, due to internal faults, as well as insulation faults or regulation malfunctions. Such faults are uncommon, so protective relays must operate very rarely. If the protection relay fails to detect the fault, the resulting damage to the alternator or transformer may require costly repairs or equipment replacement, as well as loss of revenue from the inability to generate and sell power.