The IKI-30 is a transformer-powered Protection Relay according to IEC 60255, suitable for transformer ratings between 160. 12500 kVA, as overload, short-circuit and earth short-circuit protection in combination with circuit breakers or power isolators, as well as overload. ABB's transformer protection relays are used for protection, control, measurement and supervision of power transformers, unit and step-up transformers, including power generator-transformer blocks in utility and industry power distribution networks. The relays provide main protection for. Transformer protection schemes include both electrical and mechanical protection devices: 1.