The commencement of the National Electricity Market in southern and eastern Australia in late 1998 introduced a new competitive business environment to the nation's electricity supply industry. While this deregulated environment offers potential benefits through competitive pricing and freedom of choice when purchasing wholesale electricity, it presents significant challenges to the regulated network owners.
Powerlink (Queensland, Australia) is a regulated electricity transmission company that faces a continual challenge to reduce system operation and maintenance costs while increasing network availability and reliability. Industry practice has been to undertake routine or preventive maintenance with staff conducting regular field visits to site facilities. With a network extending to 82 high-voltage substations over almost 2000 km (1243 miles) of Queensland's east coast, Powerlink's maintenance costs, based on traditional practices, were significant and resource consuming.
Powerlink recently established an asset-monitoring strategy to reduce operational and maintenance costs, while seeking to reduce the frequency and duration of system outages. A key aspect of this strategy was the remote monitoring of critical high-voltage equiment to enable rapid diagnosis of incipient failure trends and faults prior to a system or equipment outage. Based on this requirement, Powerlink decided to adopt remote-monitoring and surveillance technology to realize the asset-monitoring strategy across the network. Powerlink met this challenge with several innovative solutions.
The operation and control of high-voltage substations requires a reliable communications network, a practice that has been an industry standard for many years. However, while most modern high-voltage substations are equipped with condition-monitoring interfaces, the conventional communication networks are unable to provide the bandwidth necessary to transfer the information to a central location.
To access the stored data, a trained technician had to download data from each site to a laptop. Thus, the project target was to enable remote login to each substation from any authorized desktop computer to interrogate all the operational equipment data available. In addition, operation of site surveillance was required.
The project comprised six major components:
Design a fully integrated system to allow remote login to the condition-monitoring facilities of substations from any authorized desktop computer. Security is paramount with risks to the power system kept to a minimum.
Develop a site security system using remotely controlled digital cameras. These cameras provide technical staff with the ability to remotely inspect equipment.
Evaluate, and upgrade where necessary, existing communications systems to provide adequate bandwidth capacity to access the available data.
Create local area networks (LAN) within substations to be linked via a wide area network (WAN) throughout the entire transmission system. This WAN is to be connected to the LAN within the main engineering and operational management areas of Powerlink's Brisbane base.
Use standard IT computer hardware and software. The reliability and availability of modern PC components means their usage in remote-monitoring tasks is now possible.
Where possible. work with manufacturers to modify their software to facilitate remote interrogation and control; when not possible, develop in-house software.
Powerlink will connect 37 high-voltage substations to its remote-monitoring system by June 2002.
Blackwall Substation, located west of Brisbane, was one of the first substations to be connected to the remote-monitoring system.
Design Innovations and Benefits
The remote-monitoring project delivered a simple and reliable remote online desktop interrogation, monitoring and surveillance system for high-voltage substations.
The following innovations minimized project costs while providing a reliable and flexible system:
Using spare capacity high-speed communication-data links previously used only for control and operations.
Integrating the corporate business support network at the Brisbane office.
Adopting available Internet technology for digital-surveillance cameras at a fraction of the cost of conventional security technology to create one of the Southern Hemisphere's largest networks of Web cameras.
Using readily available off-the-shelf components where possible.
Experience to Date
The project paved the way for new operational practices that have helped improve efficiencies in responding to system faults and routine maintenance.
The monitoring and surveillance features of the remote-monitoring system revealed several benefits and annual cost savings, including: reducing routine substation visits to once per year, saving A$150,000 (US$77,000) annually; reduced the dependency on external communication companies through the use of existing communication system bandwidth, leading to savings of A$60,000 (US$ 31,000) annually; and eliminating on-site training of operational and maintenance staff, saving A$60,000 annually.
Based on the operational experience to date, the additional data available from the remote-monitoring system following a network fault has been extremely useful. For substations with the remote-monitoring capability, site attendance can be avoided or delayed until a more appropriate time, a further 16% of the time compared to traditional sites; this has resulted in savings of A$150,000 annually in callout costs and lost opportunities. This does not include the additional benefit of providing the maintenance service provider with better information prior to the site visit, avoiding problems of not having the necessary equipment to fix the fault.
On several occasions, the remote-monitoring system has helped restore supply times by providing access to the data required to establish the most appropriate restoration strategy. In addition, it permits remote resetting of devices after confirmation of the cause of the fault using the cameras to visually inspect equipment on site.
On one such occasion the remote-monitoring system enabled a piece of equipment to be returned to service without an engineer visiting the site, which was a four-hour drive from the nearest maintenance depot. In this case, the system avoided constraining a critical feeder and its associated impact on the National Electricity Market for four hours.
Similarly, on another occasion when load shedding had occurred, the remote-monitoring system enabled the load to be restored one hour earlier than would have been possible otherwise. Estimated cost savings associated with these two incidents alone easily cover the cost of installing the remote-monitoring systems at the involved sites.
Following the successful implementation of the remote-monitoring system, Powerlink has realized several other intangible benefits:
Improved availability of accurate network information has allowed Powerlink to better manage its exposure to risk in the current National Electricity Market.
Integration of operational data and the data held in the corporate enterprise planning system has been facilitated by this project.
Improved availability of data has helped to optimize planning studies and equipment use.
Powerlink is the first Australian transmission company to invest in a complete remote-monitoring system that has updated the traditional substation operation and maintenance activities. Cost-benefit studies confirm that the savings to date, as a result of the use of the new facility and the related savings in system operational costs, will exceed the value of the total investment. The innovative nature of the remote-monitoring system and its associated benefits have been widely recognized with the system winning an Institution of Engineers Australia (Queensland Division) Engineering Excellence Award.
Simon Bartlett has 27 years of experience in the Australian, European and North American power generation and transmission industries. As general manager, Network, at Powerlink Queensland, he is responsible for managing its Network Business including revenue regulation, asset management, customer account management, external stakeholder liaison and network business development. Bartlett is a convenor of the International CIGRÉ Task Force on Asset Management, convenor of the Australian/New Zealand Substations Panel and a member of CIGRÉ International Study Committee on Substations.