2. Facility/flowgate limitations and flows at the time the TLR was initiated.

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1 Entergy TLR 5 Investigation Report Flowgate 1327 (Scott-Bonin 138kV for the loss of Cocodrie-Ville Platte 230kV) TLR Level 5A: May 23, 2005 Report Issued: 1. Description of purpose/cause of hold/curtailment. This report is submitted in accordance with the NERC Transmission Loading Relief Investigation Procedure for the TLR 5 event that occurred on Flowgate 1327 on May 23, Flowgate 1327 is an Entergy flowgate. The TLR 5 was in effect from 10:28 on May 23, 2005 until 19:31 on May 23, Projected post-contingent flows on the Scott-Bonin 138kV line for the loss of the Cocodrie-Ville Platte 230kV line exceeded the OSL with all non-firm transactions on the flowgate curtailed. Heavy post contingent loading on the Scott-Bonin 138kV line was partly caused by the planned outage of the Scott-Semere 138kV line. 2. Facility/flowgate limitations and flows at the time the TLR was initiated. At the time the TLR 5A was first issued, the Limiting Element was rated at 247 MVA. Flow on the Limiting Element was 173 MVA. Flow on the Contingent Element was 217 MVA. The LODF was approximately 37.8%. Post-contingent flow on the Limiting Element was approximately 255 MVA. 3. TLR levels, timing, and relief requested amounts. TLRs levels, timing and relief requested amounts are shown in the table below: Date Time Level Relief Requested Firm PTP Transactions Curtailed 5/23/05 08: N/A 5/23/05 09: N/A 5/23/05 10:28 5a 0 0 5/23/05 10:37 5a 6 2 5/23/05 11:33 5a /23/05 12:29 5a /23/05 13:27 5a /23/05 14:29 5a /23/05 15:31 5a /23/05 16:28 5a /23/05 17:31 5a /23/05 18:29 5a /23/05 19: N/A 5/23/05 20: N/A 5/23/05 21: N/A 5/23/05 22:30 3a 0 N/A 5/23/05 23: N/A 1

2 4. Transmission and generation outages or changes from prediction that may have contributed. The planned outage of the Scott-Semere 138kV line significantly contributed to the constraint. It was a necessary outage related to the Wells substation tie-in. 5. Procedures implemented prior to hold/curtailment. TLR Level 4 was issued prior to issuance of TLR Level 5A. 6. The initial investigation shall compare all transaction curtailment lists as generated by the IDC with the list of transactions flowing as determined by the IDC (Whole Transaction Lists) both before and after curtailment. The reasons for any transactions that were excluded from curtailment shall be provided. For those transactions not curtailed, the Reliability Authority will identify those entities and any affiliation with said entities. There were no known transactions excluded from curtailment for this TLR. 7. List of known transactions not in the IDC with Transaction Contribution Factors greater than the curtailment threshold and actions taken to curtail such transactions. There were no known transactions not in the IDC. 8. Excerpts from the RA Operations Log containing information relevant to the TLR event. The Reliability Coordinators log is shown on pages 4 and Flowgate limitations as identified by security analysis processes conducted by the Reliability Authority for the day prior to the TLR event. See pages 6 through 8 for TOPs studies. 10. State Estimator snapshots and security analysis, including any contingency analysis or stability analysis, along with any other recorded data indicating need for TLR. See pages 9 through 21 for the State Estimator snapshots. 11. ATC limitations before, during, and after the TLR event. Entergy grants transmission service using an AFC process. This process evaluates each transmission request on a case by case basis. There are no ATC values for individual corridors to or from the Entergy system. Entergy was not granting any transmission requests that impacted the congested flowgate by 3 % or greater at the time of the TLR 5. 2

3 12. Description of actions taken to avoid future hold/curtailments. This TLR is the result of congestion caused by a dearth of online generation in the Lafayette area in combination with the Scott-Semere 138kV line outage. The resulting North-to-South transfers cause overloads on the 138 kv transmission system in this area. The addition of the Wells 500/230kV substation (expected completion May/June 2005) should help to alleviate the overloading issues that have been historically seen with the Lafayette area. The Scott-Semere outage is related to the Wells substation tie-in. 13. Provide IDC generated Congestion Management Reports showing transaction curtailment list and Control Area NNL (network and native load) curtailment responsibility. Congestion Management Reports for each issuance of the TLR are shown on pages 22 through Re-dispatch actions taken. During the TLR 5a event, CLECO raised the Teche 3 unit by approximately 200MW. The GSF for the Teche 3 unit was 22.6%. Because the LAFA unit was derated, it was only able to increase generation by approximately 75MW. It s GSF was 56.6%. 3

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6 *** Contingency Results Summary. *** Total No. tested = 2398 Total LF iterations 5419 Converged = 2383 Voltage Collapse = 11 Not Converged = 4 ****** No violations encountered among selected monitored elements ****** *** MUST 5.0 *** TUE, MAY :39 *** BASED ON SEAMS BASE CASE DEVELOPED IN APRIL 2005 MAY23 Subsys.File d:\psse28\example\entergy.sub Monit.File d:\psse28\example\maac1.mon Contin.File d:\psse28\example\maac.con Exclud.File none *********************************************************************** *********************************************************************** ** Detailed Report On Non-Converged Contingencies ** *********************************************************************** *********************************************************************** ******* Contingency JACINTO CHJC_SER Branches to be opened ** From bus ** ** To bus ** CKT OutageFl JACINTO CHJC_SER ******* Contingency GRIMES GRMXF Branches to be opened ** From bus ** ** To bus ** CKT OutageFl GRIMES GRMXF ******* Contingency CHINA CHJC_SER Branches to be opened ** From bus ** ** To bus ** CKT OutageFl CHINA CHJC_SER ******* Contingency VLNTIN CLOVEL Branches to be opened ** From bus ** ** To bus ** CKT OutageFl VLNTIN CLOVEL ******* Contingency CLOVEL GMEADW Branches to be opened ** From bus ** ** To bus ** CKT OutageFl CLOVEL GMEADW

7 ******* Contingency GR-TC* HOLNDL Branches to be opened ** From bus ** ** To bus ** CKT OutageFl GR-TC* HOLNDL ******* Contingency B.WLSN VKSB-S Branches to be opened ** From bus ** ** To bus ** CKT OutageFl B.WLSN VKSB-S ******* Contingency VKSB-S PT GIB Branches to be opened ** From bus ** ** To bus ** CKT OutageFl VKSB-S PT GIB ******* Contingency BASTRP BASTAP Branches to be opened ** From bus ** ** To bus ** CKT OutageFl BASTRP BASTAP ******* Contingency ELD-NW ELD-UP* Branches to be opened ** From bus ** ** To bus ** CKT OutageFl ELD-NW ELD-UP* ******* Contingency ELD-UP* JUNCITY Branches to be opened ** From bus ** ** To bus ** CKT OutageFl ELD-UP* JUNCITY ******* Contingency AMITY * ALPINE# Branches to be opened ** From bus ** ** To bus ** CKT OutageFl AMITY * ALPINE# ******* Contingency ALPINE# BISMRK Branches to be opened ** From bus ** ** To bus ** CKT OutageFl ALPINE# BISMRK ******* Contingency BISMRK HSEHVW Branches to be opened ** From bus ** ** To bus ** CKT OutageFl BISMRK HSEHVW ******* Contingency 1539 Unit:97451 G1LEWIS 22.0 Id:1 Report on bus events 7

8 Remove unit 1 from bus G1LEWIS MW *********************************************************************** *********************************************************************** ** Detailed Report On Converged Contingencies ** *********************************************************************** *********************************************************************** ******* Contingency COCODR VILPLT Branches to be opened ** From bus ** ** To bus ** CKT OutageFl COCODR VILPLT Branches with MVA flow more than 99.9 % of nominal rating ** From bus ** ** To bus ** CKT Tp ContFlow BaseFlow Rating IntLd% SCOTT BONIN LN ******* Contingency BONIN PMOUTON Branches to be opened ** From bus ** ** To bus ** CKT OutageFl BONIN PMOUTON Branches with MVA flow more than 99.9 % of nominal rating ** From bus ** ** To bus ** CKT Tp ContFlow BaseFlow Rating IntLd% SCOTT BONIN LN

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