33kV & 66KV & 132KV Main Transformer Differential Protection Relay

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GWZC-9826 Main Transformer Differential Protection Relay

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GWZC-9826 Main Transformer Differential Protection Relay（87H | 87 | 87A）

Applicable Scope：The GWZC-9826 is a transformer differential protection relay for 33kV–110kV systems, detecting internal faults via current comparison with harmonic restraint. Installed in protection panels or switchgear, it ensures fast tripping (<30ms) for transformers in substations, GSU units, and industrial plants.

Product functions（ANSI）：87H | 87 | 87A | 60

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

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Product Introduction Technical Parameter Size

Product Introduction:

The GWZC-9826 Transformer Differential Protection Relay provides high-speed primary protection for power transformers (typically 33kV–110kV） by detecting internal faults through differential current comparison, with harmonic restraint to prevent maloperation during inrush conditions.
GWZC-9826 Transformer Differential Protection Relay Installed in transformer protection panels or HV switchgear cabinets, it is widely used in substations, generator step-up (GSU) transformers, and industrial plants, ensuring rapid fault clearance (<30ms) while offering optional backup overcurrent protection.

Product functionsANSI）：

1.Instantaneous Differential Protection (ANSI 87H)
2.Percentage Differential Protection (ANSI 87)
3.Differential Current Alarm (ANSI 87A)
4.CT Open-Circuit Detection (ANSI 60)

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