Grid automation improves safety and quality of power supply in urban networks – case JE-Siirto

Grid automation improves safety and quality of power supply in urban networks – case JE-Siirto

Network reliability is a primary concern in our growing urban hubs. JE-Siirto has therefore partnered with ABB to build a more reliable and smarter city grid with ABB’s grid automation solutions.

The global trend to update urban medium-voltage cable networks with grid automation is also being seen across Finland. One of the updaters is JE-Siirto Oy, the distribution system operator (DSO) of power utility Jyväskylän Energia Oy, owned by city of Jyväskylä in Central Finland.

JE-Siirto keeps lights on and power flowing with modern smart grid solutions where the public 4G mobile technology-based communication via ABB’s Arctic devices is a key. The first steps towards establishing a smart city grid were taken in 2009. Since then, 130 remotely monitored and controlled secondary substations have been installed around Jyväskylä city. Most of them were existing ring main units (RMU) where automation was added as a very cost-efficient retrofit.

“The grid automation level of our network is now approximately 30 percent. The ideal level would be 80–90 percent and that’s what we are aiming for in the long term. The situation now is moderate, with one to three remotely controllable secondary substations in every feeder line of our ring type network. Even so, the advantages of remote operation compared to the old situation are already evident,” said Sakari Kauppinen, operations manager at JE-Siirto. “We won’t go back to the old situation,” he stated.

Fewer and shorter outages

According to Kauppinen, the remote operation of secondary substations has meant remarkably shorter power outages or even the avoidance of outages altogether, because hidden faults can be identified and located before they cause any interruptions.

Today, in 50–70 percent of power outages, fault location, isolation and reconnection of power to healthy parts of the network, take only 2 to 3 minutes. The network operator, using the supervisory, control and data acquisition (SCADA) system, makes the first decisions quickly, executes commands remotely and thus gives peace of mind and time to react to the field team.

“Customers are never happy about outages. Industrial plants have sensitive production processes where outages or voltage peaks are not allowed, sewage treatment plants have direct connection to the environment, which means maintaining power is critical, and hospitals with operating theaters and life support machines are obvious facilities where continuous power flow is essential. The reliability and the quality of power is critical for today’s society,” said Kauppinen, as he explained the need for grid automation in the urban network.

Situational awareness improves personal safety

Besides reliability, safety is a key value, which is why JE-Siirto is investing in automation in their distribution network. Both safety and reliability have already improved significantly.

JE-Siirto has a real-time view of what is happening in their network. Ring main units (RMU) and measurement sensors in secondary substations are measuring power flow, voltages, currents and many other elements, which are valuable in identifying and locating faults. The collected data is then sent via smart devices to the SCADA system for further action.

“The development of grid automation devices has been enormous in the last ten years. Nowadays, measurement data from the secondary substations are accurate and we even know the direction of fault currents. The online monitoring and real-time data from the network matter every day, not only in fault situations. Remote disconnections and load moves make our work safer and more efficient both in planned service breaks and during disturbances,” said Kauppinen.

Earth fault is always a risk for consumers and for utility personnel, not to mention the damage it can cause to network components. Improved personal safety is also the target of the research collaboration with ABB to develop a novel earth-fault current based feeder protection. Initial results show that the novel algorithm estimates the earth-fault current very accurately compared with traditional protection schemes, therefore improving protection dependability and safety. With the novel method, timely and precise protection operation can be ensured in compliance with applied legislation during all possible operating conditions.

ABB has been the partner of choice since JE-Siirto started to automate their grid and the close co-operation to find optimal solutions continues.

Investing in future solutions

Regulatory requirements in Finland have challenged DSOs to improve supply reliability during recent years. In rural areas this has meant the so-called weather proofing of networks at large-scale by replacing overhead lines with underground cables. In towns, where cable networks are already underground, better reliability is achieved with optimal grid automation solutions.

Fewer outages are reflected directly in greater customer satisfaction. The experience of JE-Siirto proves that investing in grid automation is profitable not only in rural but also in urban cable networks where distances between secondary substations are short but crowded and where new demands are being made on the network. Increasing numbers of private solar panels and distributed energy production mixed with the growing popularity of electric vehicles and their charging facilities are challenging traditional networks.

“If you don’t react and make your grid smarter now, in a few years you will be really struggling with all coming changes,” suggested Kauppinen.

“The sophistication of the control of the flow of electricity is rapidly increasing. ABB’s teams and individuals all over the world work together with customers to secure their success. We create pioneering technology that connects our utility customers and the end consumers to a future with a smarter, safer, more reliable flow of electricity,” stated Alessandro Palin, managing director of ABB’s Distribution Solutions business.

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