1 / 13

Automatic Load Transfer – The Perfect Phantom Voltage SWEDE Conference Corpus Christi, TX May 3, 2006 Kenton M. Brannan,

Automatic Load Transfer – The Perfect Phantom Voltage SWEDE Conference Corpus Christi, TX May 3, 2006 Kenton M. Brannan, P.E. CenterPoint Energy - Distribution System Reliability kenton.brannan@centerpointenergy.com. Facilities CenterPoint Energy Everyone’s Internet (EV1) Diagram

dex
Télécharger la présentation

Automatic Load Transfer – The Perfect Phantom Voltage SWEDE Conference Corpus Christi, TX May 3, 2006 Kenton M. Brannan,

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Automatic Load Transfer – The Perfect Phantom Voltage SWEDE Conference Corpus Christi, TX May 3, 2006 Kenton M. Brannan, P.E. CenterPoint Energy - Distribution System Reliability kenton.brannan@centerpointenergy.com

  2. Facilities CenterPoint Energy Everyone’s Internet (EV1) Diagram Scenario of Events Verification & Short-Term Fix Root Cause Finding a Long-Term Solution Recommendation Closure The Perfect Phantom Voltage

  3. CenterPoint Energy 2–2500 kVA pad mounted transformers 35 kV–480/277 V, Grd–Wye/Grd–Wye 115’ 1/0 AL UDG cable from terminal poles 110’ # 2 AAAC OVH lateral Everyone’s Internet (EV1) Data Center  Complete redundancy Backup generators can support 100% facility load 3,000 A automatic transfer switch (each service) Currently 2 services, 3rd expected in 2006 Facilities

  4. Diagram of Facilities

  5. County maint. crew blew C-phase lateral fuse C-phase voltage went to 0.0 Volts Transfer switch rolled load to neutral position C-phase secondary voltage reappeared Adequate voltage detected, roll-back initiated C-phase voltage again went to 0.0 Volts Cycle continued every few seconds for 20 min. EV1 staff blocked roll-back Scenario of Events

  6. Test scheduled to verify voltage All 3 fuses in place 284, 283, 284 V C-phase lateral fuse removed 284, 284, 276 V B-phase lateral fuse removed 284, 267, 284 V Short-Term Fix 10 minute roll-back block placed on each ATS Verification & Short-Term Fix

  7. Test – All Fuses in Place

  8. Test – C-phase Fuse Removed

  9. Contacted transformer manufacturer Discarded possibilities Ferro resonance Capacitive coupling C-phase voltage 100% load transfer Result of vectoral sum of A & B-phase fluxes Shifted by 180° due to nature of XFMR core Flux induces voltage on C-phase at 240° Root Cause

  10. Continue with 10 minute block Replace the transformer Delta-wye? Shift non-critical load from ATS to XFMR How much load? Add a small load to XFMR How much load? Future? Measure primary voltage 3-phase recloser on terminal pole $50,000  $150,000 for all 3 services Finding a Long-Term Solution

  11. Focus directed toward ATS IEEE task force for ATS Additional data acquired during test N/P sequence ratio: All 3 fuses in place N/P – 0.4 % C-phase lateral fuse removed N/P – 2.1 % B-phase lateral fuse removed N/P – 6.4 % Finding a Long-Term Solution

  12. Recommendation – 47N Phase Sequence Relay Installed at ATS controls Set at 2.0 % (negative/positive sequence) Cummins installed relay Test of relay scheduled Individual fuses removed Activity of ATS monitored Recommendation

  13. 47N relay prevented roll-back Determined successful EV1’s total installed cost $6,000 (per ATS) $18,000 for all 3 services Unique Situation CenterPoint Energy ATS controls manufacturer – Cummins Closure

More Related