Low Frequency & Under Voltage Load Shedding Relay | Manufacturers Price Guide & Technical Specs

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GWZC-9890L Low-Frequency Low-Voltage Load Shedding DeviceGWZC-9890L Low-Frequency Low-Voltage Load Shedding Device

Low-Frequency Low-Voltage Load Shedding Device Side View

Low-Frequency Low-Voltage Load Shedding Device Rear View

GWZC-9890L Low-Frequency Low-Voltage Load Shedding Device

Applicable Scope：GWZC-9890L Underfrequency and Undervoltage Load Shedding (UFUVLS) device serves as an emergency protection measure for power systems. It automatically sheds partial loads to restore balance when grid frequency drops due to power deficit or voltage declines from reactive power deficiency, preventing frequency collapse or voltage instability while avoiding widespread blackouts. This device is particularly suitable for complex grids with high renewable energy penetration.

Product functions（ANSI）：IEEE C37.2: 27L1, 27L2, 27L3 | 59L1, 59L2, 59L3 | 81L1, 81L2, 81L3 | 81O1, 81O2, 81O3

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:

GWZC-9890L Underfrequency and Undervoltage Load Shedding (UFUVLS) device serves as an emergency protection measure for power systems. It automatically sheds partial loads to restore balance when grid frequency drops due to power deficit or voltage declines from reactive power deficiency, preventing frequency collapse or voltage instability while avoiding widespread blackouts. This device is particularly suitable for complex grids with high renewable energy penetration.

Product functions（ANSI）：

Undervoltage Load Shedding ( 27L1, 27L2, 27L3)
Overvoltage Load Shedding ( 59L1, 59L2, 59L3)
Underfrequency Load Shedding (81L1, 81L2, 81L3)
Overfrequency Load Shedding (81O1, 81O2, 81O3)
PT Fuse Failure Alarm (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