Chapter 1 Introduction
1
Chapter 1 Introduction
About This Manual
This manual is intended to assist the user in the installation of the
eXpert
meter
™
EM720
POWER
QUALITY REVENUE METER Unit
. The term ‘
EM720’
’ is used herein to refer to all models in the series.
This chapter gives an overview of this manual and an introduction to the
EM720.
Chapter 2,
Installation
, provides instructions for mechanical and electrical installation.
Chapter 3,
Communications
, provides drawings for communications connections and instructions for
printing electrical parameter readings.
Technical Specifications for the
EM720
are found in the
Appendix
.
About The EM720
The
EM720
series is a group of state-of-art multi-microprocessor-based digital instruments that
incorporate the capabilities of a power quality analyzer, energy meter, fault and data recorder and
programmable controller, oriented for substation, industrial and commercial areas. These instruments
provide three-phase measurements of electrical quantities in power distribution systems, monitoring
external events, operating external equipment via relay contacts, fast and long-term on-board recording
of measured quantities, transient voltages measurements up to 2KV, fault recording of currents up to
50A, harmonic analysis and disturbance recording.
The unit is available in three models:
•
EM720 - Basic model – offers energy meter class 0.2S, IEC Power Quality Analyzer according to
EN50160 Standard, all the basic metering, control, and fault and event recording capabilities
•
EM720T – Transient Recorder model – adds transient recording capabilities
•
EM720U – IEEE Power Quality model – based on IEEE 1159 Standard instead of EN50160
Standard
Features
The
EM720
combines in a single enclosure:
•
Precise Class 0.2S Active Energy and Power Demand Meter, Multiple Tariffs & Time-Of-Use (TOU,
16 Summary energy and demand registers for substation energy management, accumulation of
energy pulses from external watt-meters, block and sliding demands), transformer and line losses,
unique anti-tampering and self-test functions
•
State of the art Power Quality Recorder (onboard PQ analyzer according to EN50160;
programmable thresholds and hysteresis; ready-for-use reports; sags/swells, interruptions,
frequency variations; flicker, temporary overvoltages, transient overvoltages, voltage unbalance,
harmonic and interharmonics voltages)
•
Digital Fault Recorder (onboard fault detector - programmable fault thresholds and hysteresis, up to
50 Amps fault currents, zero-sequence currents and volts, current and volt unbalance; under-
voltage, neutral current; ready-for-use fault reports - fault currents magnitude and duration,
coincident volts magnitude, fault waveforms and RMS trace)
•
Event Recorder for logging internal diagnostics events, control events and I/O operations
•
Four fast Waveform Recorders; selectable AC sampling rate of 32 - 1024 samples per cycle; 20
pre-fault cycles, 1-ms resolution for digital inputs; up to 3 min of continuous recording with an 8 M-
byte onboard memory at a rate of 32 samples per cycle, expandable up to 16 M-byte at meter shop
•
Sixteen fast Data Recorders (from ½ cycle RMS to 2-hour RMS envelopes; up to 20 pre-fault
cycles; programmable data logs on a periodic basis and on any internal and external trigger)
•
Programmable Controller (32 control setpoints, OR/AND logic, extensive triggers, programmable
thresholds and delays, relay control, event-driven data recording)
•
High-Class 3-phase Power meter (true RMS of volts and amps, powers, power factors, neutral
current)
•
Demand Meter (amps, volts, harmonic demands)
•
Harmonic Analyzer (to 128’th harmonic volts and amps, directional power harmonics and power
factor, phasors, symmetrical components)
•
16 programmable timers from ½ cycle to 24 hours for periodic recording and triggering operations
on a time basis
•
Low and High range isolated Three-Phase Power Supply unit from the measured voltage inputs,
according to the voltage measurement input range:
−
Low Range measurement input nominal rating: 57.7V AC to 120V AC (L-N)
−
High Range measurement input nominal rating: 230V AC to 277V AC (L-N)
•
NiMH rechargeable backup power supply unit.
•
Optional Low DC Auxiliary power supply unit
•
Three slots for hot swap field installable option modules
•
Graphic LCD display
