Review Incident Shin.. - authority for electricity regulation, oman

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Executive Summary On 27 August 2007, at 22.07h a fault on the 132 kV-line of the Oman Electricity Transmission Company SAOC (OETC) from Wadi Jizzi to Shinas led to an interruption of the power supply in the Shinas area. This area was completely without power until 07.35 h the following day, when the supply was partly restored via the 33 kV feeders of Majan Electricity Company SAOC (MJEC) using a rota load shedding scheme. The Shinas 132 kV grid station was energized again by OETC at 23.55 h on 28 August 2007. After that MJEC restored the supply to all customers, which was completed at 01.34 h on 29 August 2007. The Authority for Electricity Regulation, Oman (the Authority) asked KEMA to identify the technical reasons for the interruption and investigate the overall management of the incident by OETC. The Authority is of the view that the time taken by OETC to restore supplies was unduly excessive. We have studied several documents, including the incident reports/sequence of events of both OETC and MJEC. Furthermore, we have interviewed representatives of both OETC and MJEC, including both General Managers, OETC’s maintenance manager, representatives of OETC’s Load Dispatch Center and responsible people on-site, such as OETC’s operation engineer and MJEC’s local staff in the Sohar area. The conclusions of our review can be summarized as follows: the duration of the outage was influenced by a number of factors: the most important being that the Wadi Jizzi – Shinas line was not (n-1) compliant as required by Oman Transmission Security Standards and international best practice; OETC was aware the Wadi Jizzi – Shinas line was not (n-1) compliant but did not have a comprehensive plan in place to detect faults. Fault distance indicators installed at the Wadi Jizzi grid station could have reduced the time taken to locate the fault and reduce the duration of the supply interruption; Since we have only seen an expired maintenance contract, we are unable to confirm that a maintenance contract for the Wadi Jizzi – Shinas line was in place at the time of the incident; spare parts were not immediately available on site and had to be transported from remote locations. This contributed to the supply interruption being longer than necessary. The fault was located at 1.00 am whereas spare parts arrived on-site at 4.30 pm. Some 14 hours was lost by not having spare parts available close to the site; organization of the emergency response effort was ad-hoc and poorly organized - it was not always clear who was in charge for coordinating the restoration activities and some Review Incident Shinas August 2007 2 09.10.2007 vs. 2 (final)
necessary safety measures such as line earthing in both the Wadi Jizzi and the Shinas grid stations were not immediately implemented. OETC did not have a complete set of defined System Normalisation procedures and System Incident procedures in place as required by the Grid Code of Oman (OC 7, Contingency Planning Code, version 1.000). Restoration time could have been significantly reduced if appropriate procedures had been in place; We recommend that: OETC expedite the construction of a second circuit to Shinas to secure n-1 compliance; immediate implementation of the Contingency Planning Code of the Grid Code; further development of LDC procedures, and immediate implementation of the already identified training procedures and training plan; OETC include special measures (such as manual re-closing) for non-(n-1) compliant lines in dedicated procedures; Develop special arrangements with the Royal Oman Police for emergency situations; KEMA’s assessment has identified serious problems in the preparation for and the handling of the incident by OETC management. We believe it is fair to say that the impact of the incident could have been limited to a significant extent if proper preparation was in place and a more prompt and adequate response had followed. Our review reveals a significant scope for improvement to be achieved in future in order to bring the quality of operations within OETC to a level in line with what could reasonably be expected from a transmission operator operating within the Oman electricity market. Review Incident Shinas August 2007 3 09.10.2007 vs. 2 (final)
Page 1: Review Incident Shinas area 27-29 A
Page 5 and 6: 1. INTRODUCTION On 27 August 2007,
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Page 9 and 10: contract with Civil Co (we have onl
Page 11 and 12: One set of procedures is about trai
Page 13 and 14: crucial for the LDC staff to be bac
Page 15 and 16: 4.3. Spare parts Since spares were
Page 17 and 18: 4.6. Incident center As discussed i
Page 19 and 20: 5. CONCLUSIONS Based on the review

Review Incident Shin.. - authority for electricity regulation, oman

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