❓ Mr. Redman questions the Minister for Energy regarding recent power outages in Walpole and surrounding areas, particularly during the holiday period, seeking details on causes, responses, capacity, historical data, investments, reliability, and alternative solutions. The Minister provides data, explanations, and planned actions to improve reliability.
AnsweredQoN 5116Legislative Assembly
QuestionView source ↗
I refer to the recent power outages in Walpole and surrounding districts, and ask: (a) Can the Minister give the time and duration of the power outages for Walpole and surrounding districts over the recent holiday period. (April 13 to April 28 inclusive); (b) What was the reason for the outages over the school holiday period (April 13 to April 28 inclusive); (c) What actions did Western Power take in response to the outages over this period; (d) Did any of these responses include “load shedding”, and if so, when and which areas had their load shed; (e) What spare capacity is on the Walpole line, and when does the Minister believe the capacity will reach its limits, thus requiring significant upgrades; (f) Can the Minister table the outages over the Easter Period in Walpole and surrounding districts for the last 20 years; (g) Can the Minister outline significant investments on the Albany-Denmark-Walpole line made over the last 10 years; (h) Can the Minister graph the reliability of the Walpole power supply over this period; and (i) Will the minister consider alternative steps to improving the reliability of power to Walpole and surrounding districts by installing a stand alone generator as “backup” or alternatively a renewable energy solution with grid scale battery backup?
AnswerView source ↗
Answered
11 June 2019
Responded by
Minister for Energy
Response time
9 days
(a) – (b) See tabled paper no .]
For the majority of the outages listed in the spreadsheet mentioned in response to question (a), high load demand, due to a large increase in the number of people in the area over the holiday period and very cold weather, resulted in protection devices (i.e. a high voltage recloser and low voltage fuses) on the feeder tripping.
There was an outage on 24 April which involved action by Western Power and this was a result of the need to manage loads at the Albany substation, at the main 132/22kV transformer level. At that time, there were significant planned works being undertaken at the Albany substation. Load limits were being approached in the evening peak that day. As a precautionary measure, load was ‘shed’ on two feeders (the Denmark and Mount Barker lines) to avoid the risk of a major substation outage which might have resulted in an area wide blackout.
(c) Western Power personnel based in the region attended to the outages to assess the situations and check for faults. Once issues associated with high demand were identified, load was progressively restored to manage demand.
In the case of three distribution transformers in the Peaceful Bay area, low voltage fuses were replaced over the Easter Period, with one of the transformers subsequently being replaced with a larger unit on 21 April.
Western Power is currently reviewing the network in Walpole and surrounding districts, and intends to take action to mitigate the risk of outages occurring again in similar circumstances. Proposed actions include:
(d) Please refer to the second paragraph of the response to question (b).
(e) Spare capacity will vary along the line. At the Albany substation level (beginning of the feeder), the utilisation of the feeder supplying Walpole is 50% from a thermal rating point of view. From a voltage perspective, there are currently no voltage issues on the high voltage network. On this basis, no significant upgrades are expected to be necessary for the foreseeable future.
Issues affecting Walpole and surrounding districts over the recent holiday period will be addressed as mentioned in the response to question (c).
(f) It is administratively prohibitive to provide 20 years’ worth of data. Over the Easter Periods for the five years prior to 2019, there have been the following two outages:
(g) The following key investments have been made over the last 10 or so years on the Albany-Denmark-Walpole line (feeder ID “ALB 520.0”):
(h) [ See tabled paper no. for reliability of supply to the locality of Walpole for the period 2010 to 2019.
The graphs show the System Average Interruption Duration Index (SAIDI) and System Average Interruption Frequency Index (SAIFI), respectively. SAIDI indicates the total number of minutes, on average, that a customer on a distribution network is without electricity in a year. SAIFI indicates the average number of times a customer’s electricity supply is interrupted per year. Certain outages, for example planned outages and outages occurring as a result of the transmission network, are excluded.
(i) The proposed works mentioned in the response to question (c) are expected to improve the reliability of supply to Walpole and surrounding districts and mitigate the risk of outages occurring again in similar circumstances. Western Power will continue to monitor the network in the region and will take further action, if required, following a detailed assessment of the technical and financial viability of available options. Options may include those mentioned in question (i).
For the majority of the outages listed in the spreadsheet mentioned in response to question (a), high load demand, due to a large increase in the number of people in the area over the holiday period and very cold weather, resulted in protection devices (i.e. a high voltage recloser and low voltage fuses) on the feeder tripping.
There was an outage on 24 April which involved action by Western Power and this was a result of the need to manage loads at the Albany substation, at the main 132/22kV transformer level. At that time, there were significant planned works being undertaken at the Albany substation. Load limits were being approached in the evening peak that day. As a precautionary measure, load was ‘shed’ on two feeders (the Denmark and Mount Barker lines) to avoid the risk of a major substation outage which might have resulted in an area wide blackout.
(c) Western Power personnel based in the region attended to the outages to assess the situations and check for faults. Once issues associated with high demand were identified, load was progressively restored to manage demand.
In the case of three distribution transformers in the Peaceful Bay area, low voltage fuses were replaced over the Easter Period, with one of the transformers subsequently being replaced with a larger unit on 21 April.
Western Power is currently reviewing the network in Walpole and surrounding districts, and intends to take action to mitigate the risk of outages occurring again in similar circumstances. Proposed actions include:
(d) Please refer to the second paragraph of the response to question (b).
(e) Spare capacity will vary along the line. At the Albany substation level (beginning of the feeder), the utilisation of the feeder supplying Walpole is 50% from a thermal rating point of view. From a voltage perspective, there are currently no voltage issues on the high voltage network. On this basis, no significant upgrades are expected to be necessary for the foreseeable future.
Issues affecting Walpole and surrounding districts over the recent holiday period will be addressed as mentioned in the response to question (c).
(f) It is administratively prohibitive to provide 20 years’ worth of data. Over the Easter Periods for the five years prior to 2019, there have been the following two outages:
(g) The following key investments have been made over the last 10 or so years on the Albany-Denmark-Walpole line (feeder ID “ALB 520.0”):
(h) [ See tabled paper no. for reliability of supply to the locality of Walpole for the period 2010 to 2019.
The graphs show the System Average Interruption Duration Index (SAIDI) and System Average Interruption Frequency Index (SAIFI), respectively. SAIDI indicates the total number of minutes, on average, that a customer on a distribution network is without electricity in a year. SAIFI indicates the average number of times a customer’s electricity supply is interrupted per year. Certain outages, for example planned outages and outages occurring as a result of the transmission network, are excluded.
(i) The proposed works mentioned in the response to question (c) are expected to improve the reliability of supply to Walpole and surrounding districts and mitigate the risk of outages occurring again in similar circumstances. Western Power will continue to monitor the network in the region and will take further action, if required, following a detailed assessment of the technical and financial viability of available options. Options may include those mentioned in question (i).
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