Project Description

SEL-701 Motor Protection Relay

SEL-701 Motor Protection Relay

The SEL-701 Motor Protection Relay provides locked rotor, running overload, and negative sequence current unbalance protection using a patented thermal model. The thermal element accurately tracks the heating effects of load current and current unbalance while the motor is accelerating and running. You can choose from three easy settings methods:

  • Motor nameplate ratings
  • 45 standard thermal limit curves
  • Custom curve fitting

Functional Overview

14 Speed Switch
27 Undervoltage
37 Underpower
46 Current Unbalance
47 Phase Reversal
49 Motor Thermal
50N Neutral Overcurrent
50 (P,G,Q) Overcurrent (Phase, Ground, Neg. Seq.)
55 Power Factor
59 Overvoltage
60 Loss-of-Potential
66 Starts-Per-Hour
81 (O,U) Over-/Underfrequency
DFR Event Reports—Motor Starts, Motor Operating Statistics
LDP Load Data Profiling
SER Sequential Events Recorder
VAR Reactive Power

* Optional

 

Front- and Rear-Panel Diagrams

SEL-701 Front Panel SEL-701 Rear Panel
Front Rear

 

Motor Thermal Protection

The SEL-701 Motor Protection Relay provides locked rotor, running overload, and negative-sequence current unbalance protection using a patented thermal model. Add the voltage input option for metering and voltage-based protection elements.

Nameplate, Standard, or Custom Curve Setting Methods

Set protection using motor nameplate data, choose from 45 standard curves, or create custom protection curves for advanced protection.

Advanced Reporting

Motor start reports and motor start trend data support maintenance by indicating load problems early. The load profiling function tracks motor loading and use, storing quantities every 15 minutes for up to 48 days.

Internal or External RTD Module

The SEL-701 is available with an optional internal resistance temperature detector (RTD) module that monitors up to 11 RTDs. The relay offers thermal trips and alarms, thermal model biasing, RTD open or short alarms, and temperature measurement when equipped with RTD inputs.

 

Comparison

710
710-5
749M 701 849
Induction Motor Protection
Synchronous Motor Protection +
Feeder Protection
Breaker Failure Protection f f
Equipment Thermal Monitoring + + +
27/59 Under-/Overvoltage + + +
32/37 Directional/Underpower Elements + + + +
40 Loss-of-Field +
46 Current Unbalance
47 Phase Reversal
49 Thermal
50 (P,N,G) Overcurrent (Phase, Neutral, Ground)
50Q Negative-Sequence Overcurrent
51 (N,G) Time-Overcurrent (Neutral, Ground)
51 (P,Q) Time-Overcurrent (Phase, Neg. Seq.)
55 Power Factor + +
60 Loss-of-Potential + f f +
78 Out-of-Step +
81 Over-/Underfrequency + +
87 Current Differential +
Arc-Flash Detection +
Separate Neutral Overcurrent
Broken Rotor Bar Detection +
SELogic Control Equations/Remote Control Switches
Nonvolatile Latch Control Switches
Multiple Settings Groups
Breaker Wear Monitor
Event Report (Multicycle Data)/Sequential Events Recorder
Demand Meter
Load Profile Report
RTD (Resistance Temperature Detector) Inputs + + +
Ethernet +
IEC 61850 + +
DNP3 LAN/WAN +
Simple Network Time Protocol (SNTP)
Modbus TCP
Modbus RTU Outstation
Synchrophasors With IEEE C37.118 Protocol
Mirrored Bits Communications
DeviceNet + +
Accepts Wye or Open-Delta Voltage Transformers + + +
Standard Feature
+ Model Option
f This function may be created using settings

Product Literature