html{display:none} Transformer Protection | Schweitzer Engineering Laboratories

Differential Protection Relays

Flexible in application, these relays can be applied in transformer protection solutions.

Transformer Protection and Monitoring Features

Breaker Failure Protectionƒƒƒƒƒ
Transformer and Machine Current Differential 
Low-Impedance Bus Differential   
Underfrequency Load Sheddingƒ    
Undervoltage Load Sheddingƒ    
Three-Phase Current Inputs534222, 3, or 42
Three-Phase Voltage Inputs21  1+1+ 1+
Protection Elements
24 Overexcitation (Volts/Hertz)    
25 Synchronism Check      
27I Inverse Time Undervoltage (Phase, Phase to Phase, Sequential, Vsync)       
27/59 Under-/Overvoltage    
32 Directional Power     
46 Current Unbalance       
49 Equipment Thermal Monitoring   
50FO Flashover Protectionƒƒ  ƒƒ  
50 (N,G) Overcurrent (Neutral, Ground)
50P Phase Overcurrent
50Q Negative-Sequence Overcurrent
51 (N,G) Time Overcurrent (Neutral, Ground)
51P Phase Time Overcurrent
51Q Negative-Sequence Time Overcurrent
67 (P,G,Q) Directional Overcurrent (Phase, Ground, Negative Sequence)       
81 Under-/Overfrequency    
81R Rate-of-Change-of-Frequencyƒ       
87 Phase Differential 
REF Restricted Earth Fault  
Instrumentation and Control
SELogic Control Equations
Voltage Check on Closingƒƒ  ƒ  
Transformer Cooling Fan Controlƒ   ƒƒ 
Nonvolatile Latch Control Switches 
SELogic Remote Control Switches
SELogic Local Control Switches 
Analog Control Variables       
Display Points 
Multiple Settings Groups  
Substation Battery Monitor  ƒ
Breaker Wear Monitor   
Event Report (Multicycle Data)
Sequential Events Recorder 
Instantaneous Meter
Demand Meter
Load and Temperature Profile Report    
Resistance Temperature Detector (RTD) Inputs    
Built-In Web Server     
IEEE C37.118 Synchrophasors     
IEC 61850   
IEC 61850 Edition 2    
Simple Network Time Protocol (SNTP)    
Parallel Redundancy Protocol (PRP)     
IEEE 1588 Precision Time Protocol Version 2 (PTPv2)      
Time-Domain Link (TiDL) Technology       
Through-Fault Monitor 
Thermal Model/SEL-2600 RTD Module Communications  
Miscellaneous Features
Spanish Language Support       
Connectorized (Quick Disconnect) Available  

Standard Feature

Model Option

ƒ This function may be created using relay, device word bits, analog quantities, and timers.