Covering a large geographical area, Finland's transmission system is extensive, having been constructed over decades to satisfy the country's increasing need for electrical energy. Substations are located in cities as well as rural areas. The distance between the most northerly and most southerly substations is approximately 1,400 km (870 miles).
The Finnish transmission system operator, Fingrid, has divided the country into seven working areas, but it still takes up to a couple of hours for field staff to travel to the outmost substations when system disturbances or faults occur.
In 2009, as a way to decrease work hours and improve worker safety, Fingrid made the decision to move from a familiar and well-functioning procedure for power system operation to a totally new procedure involving video monitoring and remote switching.
The Finnish Transmission System
The Finnish transmission system is part of the Nordic power system, together with the transmission systems in Sweden, Norway and Eastern Denmark. There also is a direct current (DC) connection from Russia and Estonia to Finland, enabling the connection between these systems, which apply different principles. Correspondingly, the Nordic power system has been connected to the system in continental Europe through DC connections. Fingrid is responsible for the development, maintenance, operational planning and supervision of the Finnish transmission system:
- 4,100 km (2,548 miles) of 400-kV transmission lines
- 2,350 km (1,460 miles) of 220-kV transmission lines
- 7,500 km (4,660 miles) of 110-kV transmission lines
- 106 substations.
Service providers, or contractors, perform substation plant and overhead line maintenance for Fingrid. Each service provider is responsible for a single business area, such as substations or overhead lines. Contractors include Eltel and Empower, companies that operate mainly in the Nordic and Baltic countries. The service provider responsible for substations has to perform the normal switching operations required for maintenance, capital system development projects and system faults. This service provider also has on-call duty staff who respond to system disturbances and fault situations when a visit to a substation is required for investigative purposes.
Improving the Process
The existing process has been functioning well, and operators in the control rooms are satisfied with the performance of the contractors who are well organized and perform their responsibilities efficiently. The most significant goal of the operations model is that field staff are able to travel to the outmost substations from their locations within two hours. This goal is demanding because the distances in working areas may be several hundred kilometers and drive time to the outermost substations in winter conditions may increase from two hours to five hours. Traveling these long distances results in extended restoration times in the event of a permanent fault, increased operational costs (both driving and working hours) and decreased safety as driving in poor weather circumstances can result in traffic accidents.
Fingrid sought to review and modify its deep-rooted work patterns and principles in power system operation as some functions were unnecessarily robust and required considerable work hours. One area the transmission system operator investigated was video monitoring. At the time, it had already invested and installed a large number of video cameras that were not being used to the full extent of their capabilities. The first video cameras were installed in two substations in the late 1990s for the overall monitoring of the substation area, including some capital-intensive components such as power transformers.
Fingrid researched information on camera techniques and identified ways in which video cameras could contribute to other operations so the utility could derive further benefits from video monitoring. However, it took the utility almost a decade to get sufficient expertise as well as courage to diversify and expand the use of video cameras to other areas of business.
The utility wanted to revise its regular operation methods and create a totally different procedure for power system operation. Even though the utility had succeeded in several benchmarking procedures, there was still room to improve the quality of operations. For example, a video monitoring system could minimize disturbance times and speed up the restoration of supplies following an outage.
The costs attributable to regular switching would be decreased, and travel times and driving distances diminished. Also, safety at work would be improved as personnel would not be required to travel long distances, and it would not be necessary to work adjacent to the electrical plant in substations.
Beginning a New Era
In the beginning of 2009, Fingrid launched a project to apply video cameras and remote-control switching to regular operations and during power system disturbances. The objective was to replace mechanics working at substations with a modern technique while retaining high-quality personnel safety standards and power system operations. According to the utility's current strategy, remotely monitored switching capability will be installed in every substation by 2025.
A number of manually controlled disconnectors and earthing switches are in the utility's older substations. These devices will have to be refurbished or replaced with motor-driven mechanisms and remote-control capability. Substations have to be equipped with a sufficient number of video cameras, which is why the project is being implemented over a long period, allowing for the refurbishment of existing substations and the construction of new substations. The utility will deem it unnecessary to install cameras if a substation is scheduled for reconstruction within a period of two years.
The first fully remotely managed and operated switching stations were commissioned in fall 2010. The deployment will continue gradually as substations are reviewed to determine the strict requirements. Currently, some 10 substations are involved in remote-control operations, and Fingrid estimates the annual rate of commissioning substations fully equipped for remote switching will be 10 substations. The system has already proved to be capable of switching operations, but accurate data on the operational performance is not available yet since the project was implemented only recently. However, it is important to note that some faults have been cleared as a result of this new operational feature, and it was invaluable when dealing with a bus bar fault.
The number of cameras installed per substation will depend on the configuration of equipment within the substation. Some small and simple substations may be handled by three or four cameras, but larger substations may require more than 10 cameras because of several voltage levels, long bus bars and a large number of transformers. Thus, the cost of providing a substation with camera surveillance is variable, but on average, the cost per substation is expected to be about 70,000 euros (US$99,000).
Description of the System
Fingrid opted to integrate the remote-control supervisory control and data acquisition (SCADA) system and video camera application to create combined technical instruction for managing and controlling switching in various situations. The created application called XADRC has been derived from combining the SCADA system XA/21 with the camera management framework DRC, which is the acronym that the Finnish camera system company Noatek has given to this product. DRC controls the installed cameras and sensors at the substations and other energy distribution facilities, and manages the video streams.
The project was executed in cooperation with the vendor of video cameras, with the objective to create an extensive future-proof network of video surveillance for operational use at substations. The product had to satisfy a strict specification that required the video cameras to be lightweight, easily adaptable and robust. The application had to achieve all the benefits of operational camera surveillance while being a flexible, robust system that would be easy to maintain and extend.
Remote control is not a new approach; it is used globally in power system operation among transmission system operators and other utilities. A new feature of the control system, however, is that it enables control center staff to verify visually the position of primary control equipment, particularly disconnectors and earthing switches. Visual verification is essential as the remote-control commands are executed at the substations, so the feedback from the local site to the SCADA system can be incorrect if the primary equipment is malfunctioning or the disconnectors or earthing switches fail to fully latch.
In the control center, the operator using SCADA selects a piece of equipment to change the status, such as a disconnector at the substation. During this action, the SCADA system transmits data packets with the IP address of the operator's workstation, point type, corresponding point number of the controlled plant, the name of the substation, the point name and the sequence number of the video monitoring server.
The video monitoring server receives the packets and starts transmitting the video of the selected equipment to the operator's desktop. When a single piece of equipment is selected, the XADRC application starts transmitting real-time information to the XADRC workstation, and the operator's workstation starts to show the video of the selected equipment.
The XADRC client viewer always shows a quad display, or a 2-inch by 2-inch (50-mm by 50-mm) video matrix. If the substation requires the disconnection of all three phases, the application shows the whole object with all three phases in the first screen. The second screen shows a picture of the first phase. The third screen shows the second phase. The fourth screen shows the third phase. The pictures are updated every 3.5 seconds on each screen during the whole process, which takes 45 seconds in total. After 45 seconds, the XADRC client's windows are minimized on the operator's screen. The time limit is configurable in the server's configuration files.
The majority of the cameras used are high-speed dome cameras. The performance of these cameras is proven, but improvement is still needed. The use of fixed megapixel cameras and megapixel dome cameras should be considered, as these cameras can scan a larger area of the substation, which can then be fully covered with the camera surveillance. The cost of a fixed megapixel camera is significantly lower than the cost of a high-speed dome camera, but the cost per installed megapixel dome is only slightly higher than the cost of a conventional video camera.
Lessons for the Future
It is not easy to transition from a familiar and well-functioning procedure to a totally new procedure. Fingrid has achieved a satisfactory level of cooperation with its service providers over the years and can rely on the expertise of the field staff. The new approach starts a totally new era in power system operation in Finland. Therefore, it is essential to recognize and identify certain features that have to be focused on as a result of this culture change.
In the former procedure, the field operative in a substation was a specialist engineer with knowledge of the operational features of the substation. In the remote monitored switching procedure, an operator in the control center requires similar expertise to exercise a new range of duties and responsibilities. Issues involved in checking the proper function of the substation is vital to be able to identify inoperative disconnectors or earthing switches. Therefore, it is essential to establish training for control center staff on the operational features of substation equipment to ensure they have the required skills to guarantee safety at work and power system security.
Solving system operational problems can be challenging, particularly those created by weather conditions such as lightning. In Finland, ice and snow collect on cameras, and daylight hours are short for six months out of the year. Therefore, video cameras have to be equipped with electrical heating to be capable of melting the ice and snow, and they have to be capable of transmitting clear pictures in poor lighting conditions. These major problems have been overcome; moreover, camera lenses are covered with a special foil that protects them from dust and dirt.
The operation of disconnectors and earthing switches require monitoring, and remedial action must be taken in the event a fault requires repair immediately. Field staff mechanics are trained to ensure proper function of the substation, especially during wintertime.
The planning process has to be improved. This requires the specification of the exact number of cameras located in precise positions at the substation, a task that has been very difficult for Fingrid. It appears that some disconnectors are screened by other items in the substation such as bus bars so that either cameras have to be relocated or additional cameras have to be installed. Management of the project has to improve by considering 3-D planning applications, improved video camera control specifications and closer cooperation with project field teams.
There is always the possibility to operate a substation manually. However, this type of action is forbidden. All remotely operated substation equipment is labeled, informing field staff that only remote control is allowed. Moreover, manual operations are prevented by mechanical locks.
Additionally, unintended remote control also has to be prevented by SCADA to guarantee safety at work and power system security.
Kimmo Kuusinen (firstname.lastname@example.org) is the senior adviser in power system operation for Fingrid, the Finnish transmission system operator. Kuusinen, who has been with Fingrid for 14 years, has held several positions in power system operation during his career. He holds a MSEE degree and an MBA degree.