How to connect to a protective relay: ports and software

What you need to connect to a relay

A numerical protective relay is an industrial computer with its own operating system, its ports and its own way of authenticating whoever connects. To read or configure it from a laptop, three things must match:

1. A physical port and its parameters: the type of connection the relay has and the configuration of that port (baud rate on serial, IP address on Ethernet).
2. The manufacturer’s software with the right driver: each brand has its tool and, inside it, a driver or package per model and firmware version.
3. An access level: the account or password that allows reading, operating or changing settings.

If any of the three fails, the symptom is the same: the program does not see the relay. That is why it pays to check them in that order.

Relay ports

In practice:

• SEL keeps front serial ports on much of its line and adds USB or Ethernet depending on the model.
• Siemens SIPROTEC 5 uses the front USB port for the local connection with DIGSI 5, in addition to the rear communication modules.
• ABB and Hitachi Energy Relion use the front service port for PCM600 and the rear ports for the substation network.
• Schneider MiCOM and Easergy and GE Vernova Multilin combine front ports (serial or USB) with rear Ethernet depending on the family.

The rear port on the substation network is the one used by the bay controller and the SCADA system. Plugging a laptop in there means entering the protection and control network: it is done only with authorization and following the site’s secure remote access rules.

Each brand’s software and driver

Each manufacturer has its tool, and each tool needs to know the relay model and firmware version. What each program does is summarized in relay configuration software by brand:

• SEL: AcSELerator QuickSet, with the driver for each device; SEL Compass keeps software and drivers up to date.
• Siemens: DIGSI 4 for SIPROTEC 4 and DIGSI 5 for SIPROTEC 5, with the device packages of the project.
• ABB and Hitachi Energy: PCM600 with the connectivity package for each family and version.
• Schneider: Easergy Studio for MiCOM, Easergy Pro for Easergy P3 and SFT2841 for Sepam.
• GE Vernova: EnerVista UR Setup or 8 Series Setup, depending on the Multilin family.

What each tool does, which files it produces and what is most often looked up is in the software guides for each brand, at the end of this page. The common rule is that the software and driver version must support the relay firmware: software older than the relay does not recognize it, and a settings file from another firmware version may not open, or may open with differences.

Why the program does not see the relay

A frequent cause on Ethernet is the laptop itself: several active network adapters, a corporate VPN or a Windows firewall blocking the manufacturer’s protocol. On serial, the typical error is a USB converter without the proper driver, or assigned to another COM port.

Access levels and permissions

Connecting does not grant permission for everything, as explained in relay access levels and passwords. Relays separate reading, operation (open and close, reset) and changing settings into levels or roles, each with its own password or account. Default passwords must be changed when the relay is placed in service and recorded in a system controlled by the owner. IEEE 1686 describes the security functions the device must offer; we explain it in IEEE 1686: IED cybersecurity requirements.

Risks of connecting to an in-service relay

Reading is safe. Writing is not always. Before changing anything in an energized relay, keep in mind:

• Read and save first. Download the settings as they are in the relay and compare them with the project file. The office file and the field file do not always match.
• Sending a complete file restarts functions. In many relays, sending settings restarts the protection for a moment or changes the output logic.
• Active settings group. Changing the active group changes the protection immediately.
• Forcing outputs or inputs. Commissioning tools allow contacts to be forced; in service, a forced output can open a breaker.
• Events and oscillography. Some maintenance operations erase records. If there was a recent trip, save them first, as explained in downloading relay events and oscillography.

We configure your relay remotely

At Tiza Group we configure protective relays, bay controllers and recloser controls of the main brands without traveling: through your substation’s remote access, or with a person on site who connects the laptop and gives us controlled access. We read the relay, compare it with the study, prepare the file and load it with your authorization. See remote relay configuration or the brand pages, such as SEL or Siemens SIPROTEC. If the work has to be done in the field, our team does it in medium, high and extra-high voltage substations and in industry, in Colombia, or elsewhere on request.

Related guides

• Siemens DIGSI 4 and DIGSI 5 software
• ABB and Hitachi Energy PCM600, IET600 and ITT600 software
• SEL AcSELerator QuickSet, Architect and Grid software
• Schneider Easergy Studio, Easergy Pro and SFT2841 software
• GE EnerVista UR Setup, 8 Series Setup and Launchpad software
• Protective relays: types, functions and maintenance
• Is remote relay configuration secure?
• Resetting a relay after a trip: LEDs, 86 and records
• Sequence of events (SOE/SER) and event reports

References

• IEEE 1686-2022, Standard for Intelligent Electronic Devices Cyber Security Capabilities.
• IEC 62351-8, Power systems management and associated information exchange - Data and communications security - Part 8: Role-based access control.
• Siemens, DIGSI 5 and SIPROTEC 5 documentation (local USB connection).
• SEL, AcSELerator QuickSet and SEL Compass documentation.
• Hitachi Energy, PCM600 documentation and Relion connectivity packages.

Frequently asked questions