PNM ICLSS Modification - PowerPoint Presentation

PNM ICLSS ModificationPath Out Sensing San Juan (to Cabezon) to Rio Puerco– Overview – Daniel J MarquisPNM Transmission Engineering 12/11/2017 [PNM CONFIDENTIAL] 1

Import Contingency Load Shedding S cheme (ICLSS) HistoryOriginal Scheme Purpose – Arrest voltage collapse and relieve overload of the Four Corners-Ambrosia-West Mesa 230 kV line following an extreme eventApproved by WECC and Operational since 2006Modified in 2015 for Rio Puerco Expansion Reviewed by RASRS in January of 2015Added ability to remove overloads of Norton-Hernandez 115 kV line to scheme objectives following and extreme event. 12/11/2017 [PNM CONFIDENTIAL] 2

Northern New Mexico Transmission12/11/2017 [PNM CONFIDENTIAL] 3

Purpose of ICLSS ModificationsNeed to Modify Line Loss Detection: Addition of Cabezon results in splitting existing 345 kV line into two 345 kV lines. Requires modifying ICLSS input to recognized outage of either segment of the original line.Scheme was originally set to use low current to determine line loss; however, this is no longer an accurate method. With high wind generation in eastern New Mexico, low current and reversed flow on the 345 kV lines is now a normal condition. Breaker and MOD status for sensing line loss is now more appropriate. 12/11/2017 [PNM CONFIDENTIAL] 4

PNM ICLSS Logic Overview (modification in red) 12/11/2017 [PNM CONFIDENTIAL] 5 Line Loss Modified to key on breaker or mod status instead of current. Insert Cabezon

Proposed Change to Path Out Sensing: Sub-paths “San Juan to Rio Puerco”Adding Cabezon Station in middle of the “San Juan to Rio Puerco” path. Cabezon will feed a third party utility radially. Need to update sensing to account for new “San Juan to Rio Puerco” sub-path outages. 12/11/2017 [PNM CONFIDENTIAL] 6

Proposed Change to Path Out Sensing: Sensing Method Current Sensing is no longer effective due to Increased Wind, and has been replaced by Breaker Status. PNM will be adding MOD open conditions. 12/11/2017 [PNM CONFIDENTIAL] 7

Existing – Path Out Sensing: San Juan (SJ) to Rio Puerco (RP) 12/11/2017 [PNM CONFIDENTIAL] 8

Existing – Path Out Sensing: San Juan (SJ) to Rio Puerco (RP) Line relays at San Juan (SJ) sense local SJ breaker status, declare “path out” if both SJ breakers are open, transmit “path out” to line relays at Rio Puerco (RP) end. Line relays at RP end send “path out” high signal to physical, hard wired OR gates (ICLSS system 1 & system 2). Sensing relays at Rio Puerco (RP) declare “path out” if both local RP breakers are open AND there is no significant line current at RP terminal. Sensing relays send “path out” high signal to physical hard wired OR gates (ICLSS system 1 & system 2). Final “path out” signals to ICLSS system 1 and 2 are transported from Rio Puerco to Person station controllers 1 and 2, respectively, using the redundant and independent Rio Puerco to Person communications paths. 12/11/2017 [PNM CONFIDENTIAL] 9

Proposed – Cabezon Layout 12/11/2017 [PNM CONFIDENTIAL] 10

Proposed – Path Out Sensing: San Juan (to Cabezon) to Rio Puerco 12/11/2017 [PNM CONFIDENTIAL] 11

Proposed – Path Out Sensing: San Juan (to Cabezon) to Rio Puerco Redundant San Juan to Cabezon (SJ-Cab) line relays 1,2,3 at San Juan (SJ) sense local breaker and line MOD status. If a relay senses both breakers open OR line MOD open then it sends “path out” to its Cabezon (Cab) remote end line relay over the two redundant and independent SJ-Cab communications channels. Redundant SJ-Cab line relays 1,2,3 at Cabezon (Cab) sense local breaker and line MOD status and receive “path out” status from San Juan (SJ) remote end. If a relay senses both breakers open OR line MOD open OR remote end “path out” signal, then relay sends “path out” to an associated Cabezon to Rio Puerco (Cab-RP) line relay (1,2,or 3) at Cabezon (Cab) using hard wired +125VDC. Redundant Cab-RP line relays 1,2,3 at Cabezon (Cab) sense local breaker and line MOD status and receive “path out” status from SJ-Cab line relay. If a relay senses both breakers open OR line MOD open OR SJ-Cab “path out” signal, then it sends “path out” to its Rio Puerco (RP) remote end line relay over the two redundant and independent Cab-RP communications channels. Redundant Cab-RP line relays 1,2,3 at Rio-Puerco (RP) sense local breaker and line MOD status and receive “path out” status from Cabezon (Cab) remote end. If a relay senses both breakers open OR line MOD open OR remote end “path out” signal, then relay sends “path out” to both the ICLSS 1 input “OR gate” and the ICLSS 2 input “OR gate” at Rio Puerco using hard wired +125VDC. As before, final “path out” signals to ICLSS system 1 and 2 are transported from Rio Puerco to Person station controllers 1 and 2, respectively, using the redundant and independent Rio Puerco to Person communications paths. 12/11/2017 [PNM CONFIDENTIAL] 12

Side by Side– Path Out Sensing Change: San Juan (to Cabezon) to Rio Puerco 12/11/2017 [PNM CONFIDENTIAL] 13

Proposed Changes – COMM Paths 12/11/2017 [PNM CONFIDENTIAL] 14

Proposed Changes – COMM Paths Original Communication paths from San Juan to Rio Puerco were Microwave/Fiber and Fiber. Proposed changes for Cabezon include insertion of Cabezon into Fiber Path. Redundant and Independent Communications Paths are maintained. 12/11/2017 [PNM CONFIDENTIAL] 15

What PNM Is RequestingThis is a general overview.Detailed, final submittal paperwork with additional transmission planning study work is in process and will be submitted in Q1 2018. Desired in-service date for Cabezon for serving neighboring utility is April 2016.PNM is asking for WECC RAS Subcommittee to consider a special call-in meeting to review and approve changes to ICLSS. If not, PNM would request detailed ICLSS review at next regular meeting. 16 12/11/2017 [PNM CONFIDENTIAL]

Questions? Suggestions for Design Improvement? 17 12/11/2017[PNM CONFIDENTIAL]

Thank YouEnd of Slides 18 12/11/2017[PNM CONFIDENTIAL]