Features

A Phasor Measurement Unit (PMU) is a device, which measures the electrical waves on an electricity grid, using a common time source for synchronization. PMU technology provides phasor information (both magnitude and phase angle) in real time. A PMU can be a dedicated device, or the PMU function can be incorporated into a protective relay or other device. Time synchronization allows synchronized real-time measurements of multiple remote measurement points on the grid. The advantage of referring phase angle to a global reference time is helpful in capturing the wide area snap shot of the power system. Effective utilization of this technology is very useful in getting the real time behavior of the power system. To study the real-time perfomance of various algorithms developed to improve the system performace, using the real time simulation facility, few PMUs are made available in the laboratory. Typical specifications of the various PMUs available in laboratory are furnished below.

• Measurement defined in IEEE C37.118
• Phasor measurement units (PMU’s) provide information about the voltage and current at point of the network in the form of phasors.

SEL - 421

SEL-421 Relay is useful for single- and three-pole tripping schemes, compensated lines, or uncompensated lines. Protect transmission lines using five zones of phase and ground-distance elements in communications-assisted schemes, with directional over current backup protection.

General Specification

AC Current Inputs	15A continuous @ 2.71VA burden 6 Nos.
AC Voltage Inputs	0-300 L-N @ 0.8VA burden 6 Nos.
Serial communications ports	EIA-232 3 Nos. Fast Messages, DNP3 Speed 300-57600bps
Ethernet communications	FTP, Telnet DNP3, LAN/WAN, SNTP, IEC 61850 10/100BASE-T or 100BASE-FX
Synchrophasors	IEEE C37.118 50 frames/sec (50Hz)/60 frames/sec (60Hz) max.

SEL - 451

SEL-451 is useful to apply over-current protection for primary and backup, and three-pole tripping schemes on sub-transmission lines. It can make settings for up to four shots of automatic breaker reclosing for one or two circuit breakers, with synchronism and voltage checks to optimize system restoration. Built-in fault locator is useful to efficiently dispatch line inspection and repair personnel.

General Specifications

AC Current Inputs	15A continuous @ 2.71VA burden 6 Nos.
AC Voltage Inputs	0-300 L-N @ 0.8VA burden 6 Nos.
Serial communications ports	EIA-232 3 Nos. Fast Messages, DNP3 Speed 300-57600bps
Ethernet communications	FTP, Telnet DNP3, LAN/WAN, SNTP, IEC 61850 10/100BASE-T or 100BASE-FX
Synchrophasors	IEEE C37.118 50 frames/sec (50Hz)/60 frames/sec (60Hz) max.

Arbiter 1133A

Arbiter make, Model 1133A Power Sentinel™ merges precision time synchronization and power measurement features into a single PMU compatible device. It is capable of Measuring the system voltage and current magnitude, phase angle, frequency and time deviations, and tackle revenue metering challenges from a single unit. It also provides the power quality measurement information, like flicker, harmonics, interruptions, etc.

General Specifications

AC Current Inputs	0 to 20 Arms.
AC Voltage Inputs	0-600 L-N
Serial communications ports	RS-232, RS-485 and Modem
Ethernet communications	IEEE 802.31 10base-T, Ethernet, TCP/IP, Modbus, DNP 3.0
Synchrophasors	IEEE C37.118