Satellite-Synchronized Network Clock

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.

Application

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 NTP to devices on the substation LAN, such as servers, computers, and other devices that set their time through NTP or the Simple Network Time Protocol (SNTP). With 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 can serve NTP or PTP to four independent Ethernet networks. The SEL-2488  provides PRP support as a DAN device.

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.

Event Notification—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. The SEL-2488 can also provide event notification through Simple Network Management Protocol (SNMP) traps and the alarm contact.

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 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.