TRANSMISSION & INTERCONNECTION PLANNING T&D BUSINESS UNIT 1 Distance Relay Specification WECC TSS January 23,2014 Amos Ang

TRANSMISSION & INTERCONNECTION PLANNING T&D BUSINESS UNIT 2 Agenda  Purpose  Background  Relay Model Specification  Next Steps

TRANSMISSION & INTERCONNECTION PLANNING T&D BUSINESS UNIT Purpose  To get approval from TSS 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 3

TRANSMISSION & INTERCONNECTION PLANNING T&D BUSINESS UNIT Background  Started with September 8 th 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. 8 th event  One of MSRATF sub group was tasked to deal with relays  Members of the sub group included input from Planning and Protection engineers  Received MV&WG Approval in December

TRANSMISSION & INTERCONNECTION PLANNING T&D BUSINESS UNIT Existing Relay Models 5 ZLIN1PSLF No transfer trip capability; No load encroachment function; No blinders DISTR1PSSE Transfer trip capability, but requires input parameters for both end of line if no transfer trip; No load encroachment function; Limited blinder functionality; no out of step functionality ZPOTTPSLF 2 zones of protection; Assumes transfer trip; No load encroachment function; No blinders

TRANSMISSION & INTERCONNECTION PLANNING T&D BUSINESS UNIT Distance Relay Specification 6

TRANSMISSION & INTERCONNECTION PLANNING T&D BUSINESS UNIT 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 7

TRANSMISSION & INTERCONNECTION PLANNING T&D BUSINESS UNIT 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 8

TRANSMISSION & INTERCONNECTION PLANNING T&D BUSINESS UNIT 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 9

TRANSMISSION & INTERCONNECTION PLANNING T&D BUSINESS UNIT 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 10

TRANSMISSION & INTERCONNECTION PLANNING T&D BUSINESS UNIT Blinders Sub-Model  Ability to shape the zone shape 11

TRANSMISSION & INTERCONNECTION PLANNING T&D BUSINESS UNIT 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 12

TRANSMISSION & INTERCONNECTION PLANNING T&D BUSINESS UNIT 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 13

TRANSMISSION & INTERCONNECTION PLANNING T&D BUSINESS UNIT Any Questions? 14