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APEC
Earthquake Response Cooperative program on
Energy Supply Systems

Introduction to Earthquake Response of Australian Energy Supply Systems

Allan Gillespie FTSE, Hon FIE Aust
Chairman

Electricity Supply Association of Australia
8 June 2001

Introduction to Earthquake Response of Australian Energy Supply Systems
Allan Gillespie FTSE, Hon FIE Aust

1. Introduction

Most Australians do not perceive earthquakes as a serious risk to infrastructure and property. There has therefore been a general lack of consciousness of the need to consider earthquake forces when designing buildings and infrastructure. The need to respond to other natural disasters such as cyclones, severe storms, flooding and bushfires has resulted in government emergency response organisations at national and State/Territory levels. Through these organisations Australia has developed effective mechanisms to deal
with natural disasters including earthquakes. Electricity supply organisations interface regularly with the emergency response structure in Australia and are used as the example to introduce earthquake response of Australian energy systems.

2. Earthquake activity and level of risk in Australia

Australia is seismically active and earthquakes pose a substantial risk as demonstrated by the deadly magnitude of the Newcastle earthquake of 1989. This was a 5.6 Richter Magnitude earthquake and caused 13 deaths. Damage was caused to over 35,000 homes, 147 schools, 3,000 commercial and other buildings/structures) in the Newcastle - Hunter region.

When compared to plate margin regions such as California or Japan, the rate of earthquakes is lower, but relative to other intraplate regions, Australia's earthquake activity is moderate to high. The level of the earthquake hazard of Australia's more active regions is roughly comparable to that of well known seismic zones in central USA. This is around 5 to 10 times lower than in California measured in engineering terms (horizontal ground acceleration with 10% probability of exceedance in 50 years). The largest earthquake that can occur in Australia is not yet known but is expected to be above Richter Magnitude 7, roughly similar to large Californian earthquakes. For example, the 1988 Tennant Creek earthquake had a Richter magnitude around 6.9, slightly larger than the 1994 Northridge earthquake near Los Angeles (Mw=6.7) that resulted in $US 15 billion and cost 57 lives. Earthquakes offshore southeastern Australia have exceeded ML=7 and different magnitudes calculations for the onshore Meeberrie WA earthquake in 1941 ranged from 6.9 to 7.2.

3. Effect on Power Systems

Depending on their magnitude and where they strike, earthquakes can cause devastation on a scale that is greater than that of any other hazard of single origin to which the power systems of electricity supply might be vulnerable. Major items of plant can be damaged irreparably. Supply can be lost over large areas. The security of complete systems can be put at risk.

One of the most critical and vulnerable components of power systems is the substation. Power Station building structures in Australia generally comply well with seismic design requirements and historically have suffered little damage. Overhead transmission and distribution lines generally withstand earthquake forces well and apart from conductor clashing and cable termination damage, very little substantive damage has occurred.

Power Station and substation buildings yield to an earthquakes and absorb some of its energy content. Lateral forces and then return to their original state without permanent damage can displace them. Australian Standard AS 1170.4 Minimum Design Loads on Structures Par4: Earthquake Loads provides data and procedures for determining minimum earthquake loads on structures and their components with particular but not
exclusive reference to buildings, building services and architectural elements. With reference to substations, the standard gives the basic ideas of earthquake-induced forces combining with other forces acting on structures. It gives hazard maps for all Australian States and Territories.

3.1 Seismic Specifications for Substation Plant and Equipment
Items of substation plant respond to an earthquake in accordance with their seismic response characteristics. From a structural point of view and with particular reference to seismic response, the structures in a substation vary widely from the massive and nearrigid body of a large transformer, to the tall, almost slender structure of a pedestalmounted current transformer.
It is important therefore that plant specifications call for each and every aspect of operational performance to be maintained during and subsequent to earthquakes of severity up to that of the design earthquake. Alignment between moving parts that are essential to correct operation, as in switching elements of all kinds, should not be impaired.
3.2 The Substation Design Function in a Utility
When plant specifications are fulfilled, the principal seismic characteristics of each individual item of substation plant are known. As encountered in an electricity utility, the structural design function relates primarily to:
  • Foundations
  • Anchoring items of plant to their foundations
  • Designing the bus conductor system (the bus work) of a substation
  • Designing other conductors and leads
  • Designing the frames on which bus conductors and other conductors are supported
  • Designing the pedestals on which pedestal-mounted equipment is supported
  • Designing substation buildings and securing them in batteries and control, communications and protection cabinets and panels
  • Designing other structures such as lighting masts and the columns of substation lighting

3.3 Substation Seismic Design Application Guide

The Electricity Supply Association of Australia (ESAA) has developed a Substation Seismic Design Application Guide. This scope of this guide matches the scope of the above deign function.

4. Commonwealth Government Role in Emergency Management

4.1 National Emergency Management Committee (NEMC)

The National Emergency Management Committee is Australia's peak consultative emergency management forum. It is chaired by the Director General Emergency Management Australia and comprises chairpersons and executive officers of State emergency management committees (the various State and Territory peak consultative committees established to coordinate and advise on emergency management/counter disaster matters). The Committee meets annually to provide advice and direction on the coordination and advancement of Commonwealth and State interests in emergency management issues. As required, it establishes working parties to examine particular issues.

4.2 Commonwealth Government Emergency Management Organisation

The Commonwealth Government Minister responsible for disaster and emergency management matters is the Minister for Defence. The agency through which the Minister exercises this responsibility is Emergency Management Australia (EMA). The senior interdepartmental body responsible for providing policy advice and for overseeing interdepartmental arrangements for providing recovery assistance to the States and Territories is the Commonwealth Counter-Disaster Task Force

5. Arrangements at Commonwealth Level

5.1 Commonwealth Counter Disaster Task Force

The Commonwealth Counter-Disaster Task Force (CCDTF) is a senior interdepartmental committee, chaired by the Department of the Prime Minister and Cabinet, comprised of representatives of Commonwealth Government departments and agencies with a significant role to play in the provision of disaster relief or rehabilitation assistance. It is responsible to the Minister for Defence. On the advice of the Director General EMA, the Chair may activate the CCDTF during the response and recovery phase of a disaster in support of EMA activities.

6. Emergency/Disaster Plans at Commonwealth Level

Emergency Management Australia maintains and uses four Commonwealth Government disaster response plans, as follows:

  • Commonwealth Government Disaster Response Plan (COMDISPLAN) - To coordinate the provision of Commonwealth Government physical assistance in the event of a disaster in Australia or its offshore Territories.
  • Commonwealth Government Overseas Disaster Assistance Plan (AUSASSISTPLAN) - To coordinate the provision of Australian emergency assistance, using Commonwealth Government physical and technical resources, following a disaster in another country.
  • Australian Contingency Plan for Space Re-entry Debris (AUSCONPLAN SPRED) - To coordinate and control the activities of Commonwealth agencies in support of State/Territory authorities involved in locating, recovering and removing radioactive space debris and monitoring and neutralising any radiological contamination threat arising from the re-entry of radioactive space debris.
  • Commonwealth Government Reception Plan (COMRECEPLAN) - To coordinate the reception of persons evacuated into Australia following an overseas event.

7. STATE/TERRITORY ORGANISATIONS

Each State and Territory has established a peak committee of senior members of appropriate departments and agencies to consider emergency management matters. The names and functions of these organisations differ, but they are basically responsible for ensuring that proper plans and arrangements are made at State or Territory and local government level to deal with emergencies and disasters. State and Territory legislation
allows the relevant Minister to appoint an Emergency/Disaster Controller to coordinate all essential service organisation activities and to liase with the Commonwealth Counter Disaster Task Force as appropriate. Dedicated control/communication centres have been established in each jurisdiction. The organisations that are normally subject to this overriding coordination are:

  • State Emergency Service Organisation (SES)
  • Police
  • Fire Services (both Urban and Rural)
  • Communications
  • Water
  • Electricity and Gas utilities
  • Transport

The most common events subject to coordination and control are:

  • Cyclone
  • Severe Hail and Thunder Storms
  • Flooding
  • Bushfires

For each of the above, the local State Emergency Services play a pivotal role in the coordination of repair crews rescue work and restoration of services.

Except for Newcastle earthquake in 1989 there has been very little experience throughout Australia for the management and restoration of services subjected to earthquake damage.

8. State Emergency Services Organisation (SES)

The State Emergency Service is a National Network operating in each State and Territory under complementary jurisdictional legislation. It is an emergency and rescue service dedicated to assisting the community. Its personnel are almost entirely volunteer. While its major responsibilities are for flood and storm operations, the State Emergency Service provides an invaluable resource of trained rescuers to support the full-time emergency services in the event of a major disaster. In the rural areas of the States and territories, the Service provides the majority of the rescue effort, and units are involved in road accident rescue, bush search and rescue, rescue from heights and depths and many specialist forms of rescue which may be required due to local threats.

9. Electricity Supply Organisations

As mentioned above, Australian Electricity Supply organisations have little experience with the management and restoration of services subjected to earthquake damage. They do, however have considerable experience in managing the more common events such as bushfires, cyclones and storm damage. The resources available to each organisation are limited and heavy reliance is placed on the provision of resources from other electricity organisations not affected.

9.1 Coordination and Planning

Each electricity supply organisation is required to have an Emergency Management Plan. These plans, which are updated annually, are made available to the respective State and Territory counter disaster organisations. Generally the following information is included in the plans:

  • Formal Organisation Structure
  • Key Personnel and contact details
  • Emergency Management structure
  • Key Assets by location
  • Equipment and stores logistics
  • Personnel deployment
  • Backup computer and communications arrangements
  • Public and Government Relations

Usually a key executive is nominated as the controller for the organisation and forms part of the relevant State or Territory counter disaster committee.

9.2 Logistics

Because of the reliance on other electricity supply organisations, it is each organisation has to plan for an influx of personnel, equipment and stores during an emergency. Supply system maps, street guides and meal provision are some of the things that must be taken account. Radio communication is vital and mobile communication standards generally have been established which allow common emergency channels to be used between electricity supply organisations and other emergency services organisations.

Stores items such as overhead conductor, underground cable, transformers and switchgear, are not always available at short notice to enable restoration of services. Considerable work has been undertaken in Australia to achieve standardisation of these items and other hardware. This has largely been achieved on the East Coast of Australia. Prior to the major risk period from October through to April each year an assessment is made by each organisation of its stock situation and the possible availability of large critical items such as major substation transformers and switchgear from other organisations.

9.3 Disaster Simulation Trials

Most organisations carry out at least one Disaster Simulation per annum to test all procedures and processes. These simulations usually involve other emergency service organisations and some major customers that need to respond quickly to electricity supply failure.

9.4 Damage Assessment

A general weakness that has been hard to overcome is the time taken to assess damage. Quite often the damage is more widespread than thought initially and this results in extended supply outages while sufficient additional resources are mobilised. In recent years a number of organisations have moved to over resource initially and reduce if necessary. In addition office staff are being utilised to assist with damage assessment.

10. Conclusion

Australia does not have a specific structure or mechanism to respond to major earthquake damage. It has been slow to adopt design standards and guidelines that limit damage to property and infrastructure under earthquake conditions. Electricity supply organisations have not been active in designing new facilities or retrofitting old facilities to limit damage.

There is an effective coordinating emergency response structure operating across Australia that is integrated with the electricity supply response mechanisms to deal with the most common emergencies such as cyclones, floods, storms and bushfires. This structure is capable of responding adequately to earthquakes.

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