Photo Taken In Bolivia, Cochabamba. Credit: NOKIA
By Marco Velasquez and Hansen Chan
In the more than 100 years it’s been distributing electricity in Bolivia, ELFEC has seen many changes. Since powering the electric tram in 1909, the company has grown to become the second largest distributor in the country, serving 650,000 homes and businesses in Cochabamba, one of the most densely populated ‘departments’ or states of Bolivia.
Facing increasing customer demand, in 2014, ELFEC began to modernize its grid. As it did so, it realized that it also needed to address limitations with grid communications.
The company traditionally used leased lines from several telecom providers for communications links with remote customer service branches, but high latency meant these lines couldn’t be relied on to transport service data such as billing, voice or video surveillance. Additionally, ELFEC leveraged the providers’ wireless networks to connect 26 supervisory control and data acquisition (SCADA) remote terminal units (RTUs) in the field.
Likewise, four hub substations were connected point-to-point using optical ground wire cabling, which ran teleprotection between them as well as provided support for SCADA data. Services such as voice and video surveillance also ran directly connected to the substation switches. However, there was no way to segment traffic and apply quality of service (QoS) assurance to prioritize the critical SCADA and teleprotection data, and there was also no back-up transport method. As a result, communication network failure could disrupt grid operations.
The need for a robust, flexible communications network
ELFEC realized it required a more robust, flexible and dedicated communications network – one that could manage all of its assets, connecting branch offices, vital substation services and field SCADA and team communications, and could continue to support services even as demand grew and evolved.
The solution had to connect 32 remote branch customer service offices as well as dispatch communications with crews in the field. At substations, it had to serve the communication needs for protection relay, RTU and intelligent electronic devices (IED) as well as remote video surveillance. In addition, it required a secondary fallback transport network that would ensure continuity of service if the primary network went down.
In order to address this, ELFEC worked with Nokia for a utility-grade transport backbone and a mission-critical internet protocol/multiprotocol label switching (IP/MPLS) communications system.
On top of the optical fiber transport backbone, ELFEC built an IP/MPLS network using service aggregation routers deployed at each substation with two 10 Gb/s optical fiber links connecting to other substations. This provided low-latency, high-bandwidth communication services for SCADA, teleprotection and video surveillance.
For the fallback transport method, ELFEC deployed 802.11ac Wi-Fi after conducting extensive studies of the area and utilizing the high mountain sites surrounding the capital city of Cochabamba for optimal coverage. It implemented multiple-input, multiple-output (MIMO) antenna technology, which uses multiple transmitters and receivers to increase data throughout and signal resiliency. ELFEC also used a service access switch, connecting to a Wi-Fi™ access point running IP/MPLS and OSPF routing protocols atop this Wi-Fi transport infrastructure.
With the wireless transport network in place, ELFEC could then reliably connect field RTUs to monitor the distribution system and send SCADA data to the operations center. Furthermore, remote branches could also be connected to the wireless transport network.
Prioritizing vital traffic
By leveraging the router’s capabilities at each of the substations, the IP/MPLS network could now be segmented, and quality of service assurance could be applied to prioritize vital traffic such as SCADA. The RTUs could use the new optical fiber network as the primary transport method with wireless connectivity providing a back-up route.
To enhance communications between the field crews and dispatch teams, the existing analog very high frequency (VHF) radio system was upgraded to an IP-over-radio system with the IP/MPLS network providing backhaul for the traffic. The network now provides support for all grid operation communications needs, including voice, data and video.
As the rollout continues, each of ELFEC’s remote customer service branches will be provided with a dedicated 1 Gb/second link to support voice, video and data traffic and the option to use either the IP/MPLS or the wireless network as the fallback transport method.
Improved response times and reliability
The ability to segment services and dedicate the switches to coordinate and support the communications between IEDs at the substations indicates that reliability has been much improved. This has also resulted in improved grid monitoring and response times. With a robust, resilient network in place, ELFEC is now able to benefit from the same capabilities as it continues to roll out these enhancements to more substations across the grid.
About the Authors
Marco Velasquez is the ELFEC Coordinator of Information Technologies. He began his professional work at the bolivian airline Lloyd Aéreo Boliviano (LAB) and in 1997, he joined the technological team of Empresa de Luz y Fuerza Eléctrica Cochabamba (ELFEC). From 2000 to 2002 he was part of the technological team at the electrical company EMEL S.A. (Chile) in the renovation project of its seven affiliated companies in the north of Chile with the shareholding of the American Pennsylvannia Power and Light (PPL). Upon completion of that project, he returned to ELFEC as Manager of Systems Development and Manager Operations and Security TI. In 2010, he became the Coordinator of Information Technologies.