Back to smartelemfg Home
Contact us Merchants settle in
Back to smartelemfg Home
Home -Differential protection relay
GWZC-9613 FO Line Diff Relay(87L)
GWZC-9613 FO Line Diff Relay(87L)
GWZC-9613 FO Line Diff Relay(87L)

Applicable Scope:This FO Line Diff Relay is designed for 132kV and below non-grounded/low-resistance grounded systems. It provides primary (differential) and backup (overcurrent/zero-sequence) protection with integrated monitoring. Supports switchgear or panel mounting, using dedicated/multiplexed fiber channels with 2048kbps E1 interface for substation and distribution applications.

Product functions(ANSI):87L | 50/51 | 51 | 50N/51N | 51N | 81U | 49 | 79 | 60 | 60 | 60 | 60/51 | 94 | 21

Communication functions:Supported Protocols:​​IEC 60870-5-103 (over Ethernet) | MODBUS RTU (via RS-485) | IEC 61850 (Ed.2 or Ed.1, as applicable)
​Interfaces:​​2× Ethernet Ports​ (IEEE 802.3 compliant, 10/100 Mbps) | 2× RS-485 Ports​ (ANSI/TIA-485-A standard, galvanically isolated)

Other functions : Support time synchronization via communication message, SNTP (Simple Network Time Protocol) time synchronization, and IRIG-B time synchronization. Support the dot matrix printing function with serial port communication. Support the fault recording function

Product Introduction Technical Parameter Size

FO Line Differential Relay Introduction

          This FO Line Diff Relay is suitable for non-effectively grounded or low-resistance grounded systems with voltage levels up to 132kV. It provides primary protection (optical fiber pilot differential) and backup protection (overcurrent, zero-sequence, etc.) for transmission lines and feeders, while integrating measurement and control functions.

          The FO Line Diff Relay supports decentralized installation in switchgear cabinets or centralized panel mounting. It uses dedicated optical fiber or multiplexed channels as pilot communication media and is equipped with a 2048kbps E1 interface. Suitable for substations, distribution networks, and similar applications, it ensures selective protection while meeting remote monitoring requirements.

FO Line Differential Relay Protection Functions(ANSI)

1.Fiber-Optic Line Differential Protection (ANSI 87L)
2.Three-Stage Phase Overcurrent Protection (ANSI 50/51)
3.Inverse-Time Phase Overcurrent Protection (ANSI 51)
4.Two-Stage Zero-Sequence Overcurrent Protection (ANSI 50N/51N)
5.Inverse-Time Zero-Sequence Overcurrent Protection (ANSI 51N)
6.Underfrequency Load Shedding (ANSI 81U)
7.Overload Alarm (ANSI 49)
8.Three-Phase Single-Shot Reclosing (ANSI 79)
9.Bus PT Broken Wire Alarm (ANSI 60)
10.Line PT Broken Wire Alarm (ANSI 60)
11.CT Broken Wire Alarm (ANSI 60)
12.PT Broken Wire Overcurrent (ANSI 60/51)
13.Independent Tripping Circuit (ANSI 94)
14.Fault Recording (ANSI 21)

FO Line Differential Relay Protection Working Principle

1.The GWZC-9613 FO Line Diff Relay incorporates three key components:
          ①.power frequency variation current differential element,
          ②.phase current differential element,
          ③.zero-sequence current differential element.
          All three elements can implement phase-segregated differential logic.

2.Fiber Optic Channel
          Dedicated fiber optic channels shall be prioritized when the fiber core quantity and transmission distance permit. When power requirements cannot be met, multiplexed fiber optic channels may be adopted.

2048kbit/s dedicated fiber optic channel


2048kbit/s multiplexed fiber optic channel

Related products More
GWZC-9614 Bus differential protection relay
GWZC-9614Bus differential protection relay
detail
GWZC-9683 Generator Differential Protection Relay(87G)
GWZC-9683 Generator Differential Protection Relay
detail
GWZC-9691 Main Transformer Differential Protection Relay(87T)
GWZC-9691 Main Transformer Differential Protection Relay
detail
GWZC-9631Y Motor Magnetic Balance Differential Protection Relay (87M)
GWZC-9631Y Motor Magnetic Balance Differential Protection Relay
detail
GWZC-9621C Transformer Differential Protection Relay (87T)
GWZC-9621C Transformer Differential Protection Relay
detail
Technical Knowledge More
Ground Distance Protection (21G)
Differences Between Phase-to-Phase Distance Protection (21P) and Ground Distance Protection (21G)
The core difference between phase-to-phase distance protection and ground distance protection lies in the selection of measured quantities, fault response range, and connection methods. They complement each other to form a complete distance protection system for high-voltage transmission lines, both following the basic principle: operation if the measured impedance is less than the setting impedance.
2026/03/04
Generator Protection Panel
Generator Protection Relay Panel : Composition and Function
Integrating protection, measurement, and communication, the Generator Protection Relay Panel can realize the protection and control of various units, enabling unattended or minimally attended operation. It can achieve generator differential protection, rotor earth fault protection, stator earth fault protection, excitation protection, overcurrent protection, overvoltage protection, overload protection, backup protection, etc.
2025/11/25
Transformer Protection Relay Panel
Transformer Protection Relay Panel:Composition and Function
Transformer Protection Relay Panel is primarily used in automation systems for substations and distribution stations in power systems of 11kV, 33kV, 132kV and above. Its main function is to ensure that the transformer can promptly trip the faulty circuit in case of overload, short circuit, gas relay activation, and other abnormal operating conditions, thereby protecting the main transformer from damage and preventing the expansion of faults.
2025/11/24
GWZC-9613 FO Line Diff Relay(87L)
Inquiry Consultation
产品表单
code img
Inquiry Consultation
+86-17621210051
+86-17621210051
+86-17621210051
+86-17621210051
home product email
live chat
my