Protection Coordination Plan for Transmission System of Montenegro

Transmission protection system operational plan is envisaged by Montenegrin transmission system Grid Code. For the purpose of creation of such plan a study has been conducted with the following content:

• Developing a simulation model of the transmission system of Montenegro, containing 400 kV, 220 kV and 110 kV transmission lines and 400/220 kV, 400/110 kV, 220/110 kV, 110/x kV transformers, using CAPE software tool.
• Collection systematization and developing a protection system data base within CAPE protection coordination software platform. Older, electromechanical types of relays, as well as sophisticated microprocessor protection devices containing several different protection functions have been modeled. Distant, overcurrent and differential protection of lines and transformers have been analyzed in detail.
• Validation of protection system model based on recorded fault data which caused nonselective relay operation.
• Analysis of protection system coordination for two power system operational regimes. Relay selectivity assessment has been conducted by the simulation of several different types of short circuits (three phase, two phase with and without ground connection, single phase with ground connection) in different parts of transmission system (bus bars and across transmission lines), for full network topology and for individual elements out of operation.
• Defining recommendations for improvement of protection system coordination based on conducted analyzes.

Based on the simulation model with existing relay settings, simulated short circuits in different parts of transmission network and defined measures for improvement of protection system coordination, operational protection coordination plan of transmission system of Montenegro has been developed.

Type of services provided:

• Developing a simulation model of transmission system of Montenegro in CAPE software tool
• Modeling and testing of the different types of relay devices (electromechanical and microprocessor)
• Validation of the simulation model
• Simulation of several types of short circuits in different parts of transmission network
• Protection coordination analysis
• Defining recommendations for improvement of protection system selectivity