Distance Relay Specification

1. Distance Relay Specification WECC M&VWG November 6,2013 Amos Ang

2. Agenda • Purpose • Background • Relay Model Specification • Next Steps

3. Purpose • To get approval from M&VWG for model specification • To model relay behavior in powerflow and transient stability analysis • To model interactions between RAS / SPS and Protection relays • To facilitate transfer of information from System Protection to Transmission Planner • Established a phased approach to implementing more functionality • To satisfy the new TPL standards of modeling the actions of protection relays for compliance

4. Background • Started with September 8th blackout • Identified three zone distance relays that actuated • Modeling SPS and Relays Ad-Hoc Task Force (MSRATF) was formed to gather all subject matter experts to work on the recommendations from Sept. 8th event • One of MSRATF sub group was tasked to deal with relays • Members of the sub group included input from Planning and Protection engineers

5. Existing Relay Models

6. Distance Relay Specification

7. Main Components of the Relay • Generic Distance Relay Main Model • Zone Detection Sub-Model • Load Encroachment Sub-Model • Blinders Sub-Model • Transfer Trip Scheme Sub-Model

8. Generic Distance Relay Main Model • There are four main functions of the main model • Perform the logic needed from the outputs of the other sub-models • Which elements to trip (up to 5 elements) • Perform the reclosing scheme if it is available • Houses the timings for all the zones

9. Zone Detection Sub-Model • There are 4 zones that can be defined per distance relay main model • Units are in Primary Ohms • 6 different zone shapes to cover most of what is available to the Protection Engineer • Lens Shape • Circle Shape • Tomato Shape • Rectangular Shape • Reactance Distance • Impedance Distance • Ability to perform logical operations up to 3 different shapes

10. Load Encroachment Sub-Model • Function is to prevent relay from operating when load current comes into the detection zone • Units are in Primary Ohms and degrees

11. Blinders Sub-Model • Ability to shape the zone shape

12. Transfer Trip Scheme Sub-model • Transfer Trip is the term of how the relay would trip the other side of the line • This model specification starts with the simplest of them all which is the step distance transfer trip scheme – once it detects and “times out” then it trips the elements defined in the main model • Building upon this sub-model would enable the Transmission Planner to have the correct timings of which breakers opens first and how much delay

13. Next Steps • Phase 2 • Develop ways to translate the relay settings to the powerflow / stability programs (automated?) • More zone shapes (if needed) • Out of step blocking / tripping functionality • Pseudo Code for Transfer Trip Scheme and Reclosing Scheme (adopt and modify the SPS / RAS language being developed) • Stock transfer trip schemes • Stock reclosing schemes • More reclosing schemes (as needed) • Ability to select what part of the relay “failed” • More than 3 tap lines – checking impedance input • Phase 3 • Modeling in the unbalanced phase environment

14. Any Questions?