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GWZC-9851 PT protection relay
PT protection relay Side View
PT protection relay Rear View
GWZC-9851 PT protection relay
PT protection relay Side View
PT protection relay Rear View
GWZC-9851 PT protection relay

Applicable Scope:The GWZC-9851 PT Protection Relay is designed for voltage transformer (PT) protection and monitoring in 110kV and below substations. It provides overvoltage and undervoltage protection for busbar PTs and is typically installed in switchgear cabinets for reliable voltage measurement in distribution and industrial power systems.

Product functions(ANSI): 59 | 27 | 59N | IEC 61850: XCBR.AlmCCS/MMXU.AlmPTFF

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

Product Introduction

          The ​GWZC-9851 PT Protection Relay​ is designed for voltage transformer (PT) protection and monitoring in ​110kV and below​ substations. It provides ​overvoltage, undervoltage, and fuse failure protection​ for busbar PTs and is typically installed in ​switchgear cabinets​ for reliable voltage measurement and fault detection in distribution and industrial power systems.

Product functionsANSI)

​1.Overvoltage Protection (ANSI 59)
2.Undervoltage Protection (ANSI 27)
3.Zero-sequence Overvoltage Protection (ANSI 59N)
4.Control Circuit Supervision Alarm (IEC 61850: XCBR.AlmCCS)
5.VT Fuse Failure Alarm (IEC 61850: MMXU.AlmPTFF)

Electrical Specifications​

​Power Supply:​​

● AC: 85-264V, 47-63Hz (≤15% THD)
● DC: 100-370V (≤5% ripple)

​Rated AC Parameters:​​

● Voltage: 100V/√3 or 100V
● Current: 5A/1A
● Frequency: 50Hz

​Overload Capacity:​​

● Current Circuit: 2×In continuous | 10×In (10s) | 40×In (1s)
● Voltage Circuit: 1.5×Un continuous

​Power Consumption:​​

● Supply: <10W (static), ≤15W (trip)
● Current Circuit: ≤1VA/phase (5A) / ≤0.5VA/phase (1A)
● Voltage Circuit: ≤0.5VA/phase

​Digital Output:​​

● Dry contact (8A@250VAC / 30VDC)
● Dielectric: 4kVAC (coil-contact), 1kVAC (open contact)
● Operating Time: 5ms (typ) / 8ms (max)
● Mechanical Life: 100k operations

Protection Performance​

​Operating Range:​​

● Voltage: 0.5-120V (phase)
● Current: 0.02-20×In
● Zero-Seq Current: 0.05-20A
● Frequency: 35-65Hz | Delay: 0-100s

​Accuracy:​​

● Voltage/Current: ±2.5% or ±0.1V/±0.05A (whichever greater)
● Frequency: ±0.01Hz
● Settings: ±2.5%

​Trip Time:​​

● Instantaneous: ≤35ms (≥1.2× setting)
● Time-Delayed: ≤1% of setting or 35ms

​Measurement & Monitoring​

​Range:​​

● Voltage: 0.5-120V | Current: 0.02-1.2×In

​Accuracy:​​

● V/I: ±0.2% | Frequency: ±0.01Hz | Other: 0.5%
● Time Sync: ≤2ms | SOE: ≤1ms

​Event Recording:​​

● 128 protection trips/operations
● 32 self-tests/fault waveforms (COMTRADE)

​Environmental & Mechanical​

​Operating Temp:​​

● Standard: -10°C to +55°C
● Extended: -40°C to +70°C*
​Storage Temp:​​ -40°C to +80°C

​Humidity:​​ 5-90% RH (non-condensing)
​Pressure:​​ 60-110 kPa
​Compliance:​​

● IEC 60255-21 (vibration/shock)
● IEC 61000-6 (EMC)

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GWZC-9851 PT protection relay
PT protection relay Side View
PT protection relay Rear View
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