SEL-700G Generator Protection Relay

The SEL-700G provides a complete protection and synchronization solution for synchronous generators. Eliminate the complexity and cost of standalone synchronizer packages. Integrating the synchronization capability into the generator protection relay provides the most cost-effective and reliable solution.

Easily upgrade protection without cutting or drilling existing cutouts with a small form factor and multiple mounting adapters. Quickly integrate into serial- or Ethernet-based communications with Modbus®, DNP3, IEC 61850,MIRRORED BITS® communications, DeviceNet™, and other protocols.

Functional Overview

21C/ 51VC Compensator Distance, Voltage Restrained/Controlled Time-Overcurrent 24 Volts/Hertz 25G Synchronism Check 27 Undervoltage 32 Directional Power 40 Loss-of-Field 46 Neg. Seq. Overcurrent 49R Thermal Overload (RTD) 49T Thermal Model 50N Neutral Overcurrent 50 (P,G,Q) Overcurrent (Phase, Ground, Neg. Seq.) 51G Ground Time-Overcurrent 51N Neutral Time-Overcurrent 59N (64G1) Neutral Overvoltage 59S Synchronism Overvoltage 59 (P,G,Q) Overvoltage (Phase, Ground, Neg. Seq.) 60 Loss-of-Potential 64F Field Ground 64G 100 Percent Stator Ground 67G Directional Ground Overcurrent 67N Directional Neutral Overcurrent 78 Out-of-Step 81 (O,U,R) Frequency (Over, Under, Rate) 87 Three-Phase Current Differential 87N Neutral Current Differential REF Restricted Earth Fault 52PB Pushbutton Trip/Close 85 SEL Mirrored Bits Communications BF Breaker Failure BRM Breaker Wear Monitor DFR Event Reports ENV SEL-2600 HMI Operator Interface LDP Load Data Profiling LGC SELogic Control Equations MET High-Accuracy Metering PMU Synchrophasors SER Sequential Events Recorder RTU Remote Terminal Unit

Front- and Rear-Panel Diagrams

Front		Rear

Comprehensive Generator Protection

Connect the SEL-700G Generator Protection Relay across small, medium, or large generators forcomplete primary and backup protection. Adding the neutral voltage connection provides 100 percent stator ground protection, based on fundamental-frequency and third-harmonic neutral-voltage measurements. Connecting the neutral current input provides protection for solidly grounded or resistance-grounded machines.

Autosynchronizer

Replace external generator control and synchronizer relays with the built-in automatic synchronizer function. Frequency, voltage, and phase control of the generator are automatically synchro-nized and connected to the power system. Monitor the generator synchro-nization process using generator start reports and the PC-based synchroscope.

Current Differential Protection

Apply sensitive percentage-restrained current differential elements and an unrestrained element, along with synchronism check and volts-per-hertz elements, across the entire unit to protect both the generator and the step-up transformer. Optional current differential elements detect stator faults using a secure, sensitive current differ-ential function. Power transformer and CT connection compensation allows the unit step-up transformer to be included in the generator differential zone.

Breaker Wear Monitoring

Record accumulated breaker contact wear with the breaker monitor function, which uses the manufacturer’s speci-fications for defining breaker operation limits. The internal monitor tracks the total number of close/open operations and integrates the interrupted current per phase. Set an alarm to alert opera-tors when measured and accumulated quantities approach maintenance thresholds. This information facilitates proactive breaker maintenance and replacement without underutilizing resources.

Easy Communications

Choose from single or dual copper or fiber-optic Ethernet ports, or serial communications, and several protocols, including Mirrored Bits®communications and IEC 61850. Pick multiple Modbus® TCP or Modbus serial sessions for custom configuration of your application. Use DNP3 Serial or DNP3 LAN/WAN protocols.