The SEL-2488 receives Global Navigation Satellite System (GNSS) time signals and distributes precise time via multiple output protocols, including IRIG-B and the Network Time Protocol (NTP). The SEL-2488 provides Parallel Redundancy Protocol (PRP) support as a Dual Attached Node (DAN) device for NTP time distribution. With an optional upgrade, the SEL-2488 can serve as a Precision Time Protocol (PTP) grandmaster clock, as defined by IEEE 1588. The advanced capabilities of the SEL-2488 make it well-suited for demanding applications, like synchrophasors, and for substations with multiple time synchronization requirements.
Time Distribution—Configure the SEL-2488 Satellite-Synchronized Network Clock’s eight BNC ports for demodulated IRIG-B, time pulse, or modulated IRIG-B (up to four ports). IRIG-B provides time output for protection applications, synchronizing relays, phasor measurement units, and other intelligent electronic devices (IEDs) to within ±40 ns. Ethernet ports can distribute time using the Network Time Protocol (NTP) to devices on the substation local-area network (LAN), such as servers, computers, and other devices that set their time through NTP or the Simple Network Time Protocol (SNTP). With purchase of the Precision Time Protocol (PTP) option, the SEL-2488 will act as a PTP grandmaster clock, supporting both the default profile (IEEE 1588-2008) and power system profile (IEEE C37.238-2011). The SEL-2488 can serve NTP or PTP to four independent Ethernet networks.
Cable Delay Compensation—Provide time delay compensation for antenna cables and output cables on a per-port basis to preserve accuracy. The SEL-2488 Clock’s cable delay compensation ensures high-accuracy time distribution in large facilities with dispersed IEDs or in installations where antennas must be mounted high on towers.
Syslog—Log and forward event messages across an Ethernet network using standard Syslog event messaging. The SEL-2488 can store up to 60,000 Syslog messages locally and send messages to three remote Syslog destinations.
Reliability—Choose a second, hot-swappable power supply to increase dependability. The SEL-2488 operates from –40° to +85°C (–40° to +185°F); is certified to IEEE 1613 Class 2, IEC 61850-3, and IEC 60255; and is backed by SEL’s ten-year worldwide product warranty.
Authentication—Authenticate and authorize users with role-based user accounts and the Lightweight Directory Access Protocol (LDAP), increasing security and simplifying management efforts.
GNSS Vulnerability Mitigation—Maintain accurate time if Global Navigation Satellite System (GNSS) time signals become unavailable as a result of solar flares, jamming, or an antenna failure. In the event of a signal loss, the SEL-2488 switches its time source to the standard TCXO holdover, with 36 µs/day accuracy, or to the optional OCXO holdover, with 5 µs/day accuracy. Both of these holdover accuracy specifications are based on a constant temperature. In the case of a GPS spoofing attack, in which a satellite system receiver locks to a counterfeit signal, the SEL-2488 and SEL-9524B GPS/GLONASS Precise-Time Antenna use signals from the GLONASS satellite constellation to validate GPS signals and identify the mismatches in timing information that this type of attack causes.
Easy and Secure Commissioning—Easily configure the SEL-2488 with an HTTPS web interface via the front Ethernet management port, which provides a graphical SkyView display for troubleshooting signal or antenna issues. The port is enabled by default and can be disabled if desired.
Accurate—Synchronize with precise time accuracy to within ±40 ns to Coordinated Universal Time (UTC) for power protection applications. Cable delay compensation can be configured for antenna cables and output cables per port to preserve high accuracy. If a GNSS lock is temporarily lost, the standard TCXO holdover accuracy is 36 µs/day and the optional OCXO holdover accuracy is 5 μs/day.
Powerful Time Distribution—Distribute time from eight time BNC outputs and one DB-9 output, which are configurable for IRIG-B or time pulse outputs. The DB-9 port can be used with SEL-2812 Fiber-Optic Transceivers to send IRIG-B long distances over fiber-optic cable. The SEL-2488 also includes four standard Ethernet ports, which provide NTPv4. With purchase of the PTP option, the SEL-2488 will act as a PTP grandmaster clock, supporting both the default profile (IEEE 1588-2008) and power system profile (IEEE C37.238-2011). The SEL-2488 will distribute NTP and PTP to four independent networks. Ethernet ports are orderable in pairs and are available in copper as well as single- or multimode fiber.
Secure—Secure access to the SEL-2488 through X.509 certificates, user-based accounts, Lightweight Directory Access Protocol (LDAP) authentication, and complex passwords. The SEL-2488 supports Syslog, a standard for event record logging that integrates with existing log management systems. With Satellite Signal Verification, the SEL-2488, when installed with a dual-constellation antenna, uses signals from two satellite constellations to validate GNSS time signals, providing a layer of protection from spoofing attacks.
Reliable—Add power source redundancy with an optional second, hot-swappable power supply. The SEL-2488 operates in a broad temperature range of –40° to +85°C (–40° to +185°F) and meets IEEE 1613 Class 1, an electric transient and interference standard for communications products in electric utility substations.
Easy to Use—Commission and manage the SEL-2488 through a secure HTTPS web interface with SkyView and acSELerator QuickSet SEL-5030 Software. The front panel of the SEL-2488 includes an LCD multi-information display plus LEDs for status and an Ethernet management port, which supports DHCP Captive Portal for simplified access to the device web interface.
SEL-9524 GNSS Antenna
The SEL-9524 is a ruggedized GNSS antenna manufactured in our Pullman, Washington, facility and is available as an ordering option or as an accessory. It includes a dual-constellation GPS/GLONASS option or a GPS-only option. The antenna operates using 3.5–6 V and includes an LED for diagnostic information. It has a strong gain of greater than 40 dB.
SEL recommends pairing the SEL-2407 and SEL-2404 with the SEL-9524A GPS GNSS Antenna. The SEL-9524B GPS/GLONASS GNSS Antenna is to be used with the SEL-2488. The legacy 235-0113 and 235-0103 Bullet Antennas are still available in limited quantities.