A NOVEL CONCEPT FOR SUBSTATION MAINTENANCE MANAGEMENT. Rolf Nordin 1, Lars-Göran Nielsen 2 and Anders Vikman 3

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1 A NOVEL CONCEPT FOR SUBSTATION MAINTENANCE MANAGEMENT Rolf Nordin 1, Lars-Göran Nielsen 2 and Anders Vikman 3 1 Vattenfall Utveckling AB, Power Technology R&D, Sweden 2 Vattenfall Norrnät AB, Sweden 3 Vattenfall Östnät AB, Sweden ABSTRACT There is an increased demand for an improved supervision and monitoring of substations both for permanent and temporary use. The main reasons for this is that the supervision is becoming more centralised to fewer and larger control centres, outsourcing of the maintenance and insourcing of customer owned substations. A flexible solution where the same standardised hardware and software can be used in different applications in combination with a connection to Internet or Intranet is preferred. A pilot-project has been performed within Vattenfall where a TCP/IP network host was used in an application for alarm handling and as a tool for maintenance management of a substation. The goal was to find out the possibilities of the system and if it was more cost effective than a conventional system. The test equipment was installed in a 40/10 kv-substation in parallel with an existing alarm handling system and it was connected to the Intranet within Vattenfall over a common dial-up link. A Web camera and a movement detector were also installed. Software to handle data, the connection between fault signals from the supervised objects and the interpretation of the significance for the customers and the station security was developed. The software includes the information about how different signals shall be treated for operation and for maintenance purpose. When an alarm is generated in the substation the system sends it to the server and the alarm is stored in a database. In this moment an is created which is sent to the control centre. The tells what was occurring in the substation, which object that generated the alarm, the most likely cause and also which measures that has to be taken and by whom in the maintenance organisation. It is also possible to address certain s directly to the equipment supplier. A fully developed system can in addition promote increased guarantee periods and other type of service agreements in the future. The equipment supplier can also specify a service level at the purchase stadium, and an can be sent after a given operation time. The pilot-project has demonstrated that it is possible to build an on-line supervision and monitoring system of a substation at a reasonable cost. The fault indications and the maintenance information for each component can be connected to an expert system, which gives the customer of the substation as well as the utility supervisory information about suitable measures when something has occurred. The maintenance and fault repair can with this system be totally condition based and prioritisation of the measures taken can be based on the demands for the specific customer needs. Since the system use standard IT components available on the public market and a Windows GUI the training can be concentrated on the different functions and the asset management, rather than consuming time on how to handle computers. The paper describes the installed and tested system and presents some experiences from the project and visions of possible future development activities. The paper will also discuss how the system can be designed for and adapted to be an integrated part in reliability centred maintenance (RCM) program of a customer owned substation. Finally, the paper will present some visions and possible future development activities.

2 A NOVEL CONCEPT FOR SUBSTATION MAINTENANCE MANAGEMENT Rolf Nordin 1, Lars-Göran Nielsen 2 and Anders Vikman 3 1 Vattenfall Utveckling AB, Power Technology R&D, Sweden 2 Vattenfall Norrnät AB, Sweden 3 Vattenfall Östnät AB, Sweden SYNOPSIS There is an increased demand for an improved supervision and monitoring of substations both for permanent and temporary use. The main reasons for this is that the supervision is becoming more centralised to fewer and larger control centres, outsourcing of the maintenance and insourcing of customer owned substations. A flexible solution where the same standardised hardware and software can be used in different applications in combination with a connection to Internet or Intranet is preferred. A pilot-project has been performed within Vattenfall where a TCP/IP network host was used in an application for alarm handling and as a tool for maintenance management of a substation. The goal was to find out the possibilities of the system and if it was more cost effective than a conventional system. The test equipment was installed in a 40/10 kv-substation in parallel with an existing alarm handling system and it was connected to the Intranet within Vattenfall over a common dial-up link. A Web camera and a movement detector were also installed. Software to handle data, the connection between fault signals from the supervised objects and the interpretation of the significance for the customers and the station security was developed. The software includes the information about how different signals shall be treated for operation and for maintenance purpose. When an alarm is generated in the substation the system sends it to the server and the alarm is stored in a database. In this moment an is created which is sent to the control centre. The tells what was occurring in the substation, which object that generated the alarm, the probable cause and also which measures that has to be taken and by whom in the maintenance organisation. It is also possible to address certain s directly to the equipment supplier. A fully developed system can in addition promote increased guarantee periods and other type of service agreements in the future. The equipment supplier can also specify a service level at the purchase stadium, and an can be sent after a given operation time. The pilot-project has demonstrated that it is possible to build an on-line supervision and monitoring system of a substation at a resonable cost. The fault indications and the maintenance information for each component can be connected to an expert system, which gives the customer of the substation as well as the utility supervisory information about suitable measures when something has occurred. The maintenance and fault repair can with this system be totally condition based and prioritisation of the measures taken can be based on the demands for the specific customer needs. Since the system use standard IT components available on the public market and a Windows GUI the training can be concentrated on the different functions and the asset management, rather than consuming time on how to handle computers. The paper describes the installed and tested system and presents some experiences from the project and visions of possible future development activities. The paper will also discuss how the system can be designed for and adapted to be an integrated part in reliability centred maintenance (RCM) program of a customer owned substation. Finally, the paper will present some visions and possible future development activities. INTRODUCTION There is an increased demand for an improved supervision and monitoring of substations both for permanent and temporary use. The main reasons for this are that supervision is becoming centralised to fewer and larger control centres, outsourcing of the maintenance and insourcing of customer owned substations. A flexible solution where the same hardware can be used in different applications in combination with a connection to Internet or Intranet is preferred. A pilot-project has been performed where a TCP/IP network host was used in an application for alarm handling in a substation. The aim of this test project was to test a system for alarm handling and supervision of a substation and to evaluate the possibilities to use modern IT-technology with standard components and licence free software. An existing system for monitoring and supervision was already in service at the Innanbäcken substation, located in the northern part of Sweden. The existing system cost approximately US$ and is of quite simple design. Therefore, it was interesting to find a cheaper and more

3 flexible system and with a more up-to-date technique using Internet or Intranet. the server. Depending on the traffic on Internet the time to get the can vary. The new system was installed in parallel with the already existing. The new system was connected to selected alarms and it was also used for surveillance of the station. All communication was via a dial-up modem to a Web server at Vattenfall. A Web camera and a movement detector for surveillance were also installed in the substation. Software to handle data, the connection between fault signals from the supervised objects and the interpretation of the significance for the customers and the station security was developed. The software also includes the information about how the different signals shall be managed for operation and maintenance purpose. To each signal there is an which explains what it means, suggests suitable measures and methods for fault finding, possible need for expert support and the time within which the fault should be corrected. TECHNICAL DESCRIPTION Equipment The system that has been tested is a device called EnFlex MG-200 (1). It is an industrial computer system manufactured in USA. It hosts a 468 DX2 processor running under Linux operating system. The EnFlex device is quite impact resistant but not weatherproof. The EnFlex device, figure 1, has 12 input channels and 8 output channels as standard. In this test application it was added with totally of 48 input and 24 output channels. To the input channels 32 different alarm functions was connected via transducers from 100 to 5 volts. Figure 1: The EnFlex MG-200 device. Software programming The EnFlex system provides different ways to implement the functions. Scripts can be added by using the script language TCL from Sun and a special user program, which also configures the I/O-ports. Another possibility is to build ordinary UNIX applications, which communicates with the EnFlex software and use ordinary Internet technology for the information transfer. Communications The EnFlex system communicates via TCP/IP protocol with the server, figure 2. The modem is a standard Hayes compatible Powerbit modem. The server communicates with the control centre by means of and Intranet Web technology within the Vattenfall Company. From the time an alarm is generated it takes less than 60 seconds before the has reached the control centre. It takes 1 second for EnFlex to scan the 32 input channels and about 40 seconds to dial-up and connect to Figure 2: The EnFlex architecture. Web camera and movement detector The Web camera is an AXIS NetEye 200 (2), figure 3. It takes snapshots that can be viewed remotely from the control centre via the Web interface. A movement

4 detector for outdoor application was also installed. The movement detector generates an alarm when something is moving in the substation and the camera shows a picture of what occurred. FUNCTIONS Fault indication and alarm handling When an alarm signal is generated, the EnFlex device sends it to the server and the alarm is stored in the database. In this moment an is created which is sent to the control centre. The tells the most likely cause and also which measures that has to be taken and by whom. It is also possible to address certain s direct to the equipment supplier. A fully developed system can in addition promote increased guarantee periods of the equipment and other types of service agreements in the future. The supplier can also specify a service level at the purchase stadium. An can for example be generated after a given operation time. Figure 3: The Web camera as used at Innanbäcken substation. The on-line camera could be of great help at maitenance work in the substation. By means of the camera immediatelty assistance could be provided for the service personel in the substation. Personnel with less experience can be assisted from the maintenance centre via the Web camera. This will also contribute to higher personal safety. Server On the server, which is located at Vattenfall, all alarms are stored in a database. The communication between the server and the control centre is over the Intranet in Vattenfall. The operators at the control centre can logon to the server and the database. Figure 5 shows the home page of Innanbäcken substation as the operator will see it when dial-up the via Internet. From this start page the operator has access to certain functions in the substation server depending on the privileges. As an administrator (Admin) the operator has fully access to the server and the EnFlex device in the substation. The operator can dynamically change parameters for the alarms, determine which functions that shall generate an alarm or a message in case of an fault, edit the content in the alarm messages, edit the software in the EnFlex device and to maintain the alarm logger. COSTS The costs for the system is today about 7000 US$ and the installation costs approximately 4800 US$ A realistic cost for the system hardware would be about 4300 US$, and the installation costs could be decreased when a number of installations have increased. Figure 4: The principle for fault indication and alarm handling. Some examples of events in the substation that generates an alarm to the server: - oil leakage - transformer temperature - relay protection fault Figure 6 shows an example of a fault indication and an alarm (in Swedish) sent by the substation to the mailbox at the maintenance or control centre. In this case a miniature fuse which is connected to the auxiliary voltage supply to a circuit breaker has been released. The malfunction is considered as hazardous. The also provides information about the fault, which object that is concerned, possible cause and what measures that has to be taken. Surveillance This function was intended to detect movement events in the station. When a movement is detected the camera takes a number of photos. The photos are then attached to an , which is sent to a number of selected recipients where a security company can be one.

5 A movement detector combined with a web camera gives a visual view of the station on-line and gives a possibility to an instant connection with the station and a picture of the situation. Possible occasions can be a fire alarm, movement detection or if the light is switched in the substation yard. A number of photos covering the substation are stored in the WEB-server. It is possible to walk around in the substation through these pictures off-line. RESULTS AND EXPERIENCES The EnFlex has proven to be easy to use and has a great potential for development. Despite some problems with the software and the hardware, it was possible to configure EnFlex for the intended functions. There still is a lack of security in the system and the security level has to be increased. It is possible for a hacker to enter the system. When this is solved there are almost unlimited possibilities in using this. Another problem is that you can not guarantee the deliveries. In the current state the system is functioning as a supplement to the existing system in the station and it provides a number of additional functions. The EnFlex system is user friendly. By means of the Web interface anyone with a minor experiences of Internet could handle the system. It is easy to adapt different functions to the system. All types of signals can be handled. The result shows that the tested system was easy to use and that it has a great potential for future development. Some examples are presented in the section VISIONS. TRAINING Nowadays, with immediately access to Internet or Intranet at the desk, the training on the system described here would make it more simplified thanks to the standard computer components. The training could be concentrated on the system, its functions and possibilities as a tool for asset management, rather than to consume time to learning to handle a special designed system. Thanks to the Web interface, standard components and public software, anyone with even minor experience can handle the system. VISIONS The project has demonstrated that it is possible to build an on-line supervision and monitoring system for a substation to a reasonable cost. The fault indications and maintenance information for each component can be connected to an expert system, which gives the operator information about suitable measures when something has occurred. The maintenance and fault repairs can with this system be totally condition based and prioritisation of the measures taken can be based on the demands from the customers. The visual opportunity of the system facilitates an easier remote communication with experts. Some examples of possible future developments are: - Let the system handle certain alarms by itself. For example, start a fan when the temperature is too high. - Integrate the system with an existing system for supervision in the control centre. - Integrate module for on-line monitoring of tapchanger, for example number of switchings, inservice time, etc. - Integrate module for monitoring of outdoor temperature and loading for cumulative life consumption of transformers. - Integrate module for acoustic (vibration) on-line monitoring for testing of circuit breaker. For example, a circuit breaker could be continuos monitored in-service by means of acoustic sensors connected to the system for diagnosis. When the circuit breaker is tripping, the sound (the mechanical vibrations) is recorded and compared with the sounds from previous trippings stored in server. - Integrate modules for substation surveillance, movement detection, and 360-degree remote controlled Web camera to provide a quick survey of the substation. - Module for use in customer owned substations. - Platform for implementing new diagnostic tools and sensor technologies. Since the system and components described in this paper are quite general it is also suitable for other applications where remote condition monitoring is needed. The following is a few examples where such a system could be applicable. - Remote condition monitoring of rotating machine rotor dynamics and health. - Remote monitoring of vibrations in windmill pillars. - Remote monitoring of real estates, e g. surveillance, guidance, ventilation, out- and indoor temperature and of air-condition equipment.

6 REFERENCES (1) EnFlex MG-200. EnFlex Corporation. (2) AXIS NetEye 200 Network Camera. AXIS Communications. (3) R Nordin, L-G Nielsen et al., A novel approach to supervision and monitoring of substations., NORDAC2000 conference, Trondheim, Norway, Figure 5: The home page of Innanbäcken substation as the operator will see it when dial-up via Internet.

7 Figure 6: Example of an alarm (in Swedish), sent by the server at Innanbäcken substation to the mailbox at the maintenance and control centre. In this case a miniature fuse to the auxiliary voltage supply has released. Figure 7: The principle for fault indication and alarm handling. When something has occurred, the server at the substation will automatically dial-up the server at the company, sending an with appropriate information to the mailbox at the maintenance centre. The personnel will take care of the and appropriate measures can be taken based on the information from the substation.