A new fault isolation and automatic energization scheme for inverter interfaced distributed energy resource using autorecloser

At present more number of renewable generation units are being integrated to power system at distribution level. With the increased energy penetration, reverse in conventional power flow direction and different type of integrated renewable energy, existing over current based distribution protection philosophies needs to be enhanced. This paper presents protection scheme for inverter interfaced distribution system, using voltage transformers on either side of the recloser breaker and with the application of directional overcurrent elements, directional low voltage ride through element to the existing autorecloser logic. This scheme results in human intervention only during permanent fault condition and synchronous automatic energization of power system for temporary faults, without the need of communication system. With sufficient reactive power banks and better operational control at inverter, intentional islanding scheme can be realized for unfaulted section of system during permanent fault condition. This can provide reliable power to consumers and better revenue realization for the generated green power.