EPR Modernizes Their Multinational Transmission System

“In our Central American countries, despite the fact that we have a lot of unity, we still do not have a system of open borders,” says Carlos Farfan, operations and maintenance manager at EPR. “This creates a very different challenge compared to a typical, traditional transmission company that operates in a single country.”

In addition to overseeing 1,796 km of 230 kV transmission lines, EPR manages high-voltage protection, metering, and control equipment in substations belonging to other transmission companies. The fact that EPR must manage equipment in substations they do not own is another challenge—one that makes it more difficult to access devices in person while also extending access to people who work for other companies (which is an important consideration for security).

EPR responded to these challenges with targeted modernization efforts. They envisioned advanced tools that would improve their system visibility, making it easier to record a fault, identify its cause, pinpoint its location, and dispatch repair crews efficiently. They also wanted to reinforce substation cybersecurity by enhancing the system they used to remotely access devices. To accomplish their vision, EPR leveraged their longstanding relationship with SEL.

EPR had previously used SEL protection equipment and developed a close working relationship with customer support. But this modernization effort would require advanced wide-area communications as its base, which led them to the SEL ICON Integrated Communications Optical Network platform.

“It all started with their backbone communications network between the six countries, which was modernized with ICON,” says Eduardo Palma, regional technical manager at SEL.

The ICON provides the reliable wide-area communications needed for several key technologies that EPR uses, including line-differential protection, synchrophasor collection, and advanced traveling-wave fault locating. 

“On top of the ICON, we mounted our traveling-wave fault-locating protection system, which has given us great accuracy,” says Farfan.

Traveling-wave fault locating, provided by the SEL-411L Advanced Line Differential Protection, Automation, and Control System, is much more precise than traditional impedance-based methods of locating faults. By measuring the arrival times of the traveling waves that faults produce, traveling-wave technology can pinpoint fault locations to within 300 meters (1,000 feet), independent of the length of the transmission line. More precise fault locating has allowed EPR to improve their response times without having to expand their maintenance team.

SEL-411L devices also serve as phasor measurement units, capturing synchrophasors that provide additional information to support fault-locating efforts. With the geographic hurdles that EPR faces, the ability to compare data between fault-locating tools and identify locations with conviction is especially important.

“This is a multinational transmission system,” says Palma. “So, when an operator is dispatching maintenance, he doesn’t want to dispatch the Costa Rican crew when the fault actually happened across the border on the Panama side.”

Considering its expansion plans and current challenges in accessing devices in person, EPR modernization efforts also prioritized secure remote access to substation equipment. They chose the SEL-3620 Ethernet Security Gateway and implemented layered defenses that included role-based access control for employees, IED password rotation, and meticulous logging of employee access and any changes made to devices.

“The implementation of the cybersecurity system allows engineers to have reliable and remote access to facilities and protection,” says Jorge Mario Méndez, regional substation coordinator at EPR. “That also allows us to have remote and secure collection of events for an appropriate post-failure analysis to avoid the risk of intrusion by an unwanted person.”