Deskripsi
Small Current System Grounding Microcomputer Line Selection Device
Model : ZF-WXJ
MFR : Zefan Electric Power Technology Co., Ltd.
Specifications :
- Power Supply : AC220V ±10% or DC220V ±10%
- Power Consumption : ≤ 20W
- Operating Temperature : -10°C to +55°C
- Humidity : ≤ 90% RH
- Voltage Level : 1–2 levels
- Bus Segments Supported : 1–4 segments
- Outgoing Circuits : 12, 24, 36, or 48 (customizable)
- Zero Sequence Voltage Input : 100V (PT1–PT4)
- Zero Sequence Current Input : 0.5A (CT1–CT48)
- Communication Interfaces : RS232, RS485 (default), RS422; Protocols: Disa, Modbus, XJ103
- Alarm Output : Relay contact, DC220V 5A
- Display : Large-screen LCD with LED backlight
- Memory : Stores up to 30 fault records; retains data after power-off
- Processor : Dual ARM chips for acquisition and analysis
- Additional Features : Voice alarm, fault line naming, tripping output, harmonic suppression
Product Overview
A low-current system refers to a power system whose neutral point is ungrounded, grounded via a high-resistance resistor, or grounded via an arc suppression coil. The most common fault in this system is single-phase ground fault. The grounding current in a single-phase ground fault is relatively low. According to power system safety operation regulations, the system can continue to operate for one to two hours after a single-phase ground fault. However, during this period, the system’s non-fault phase-to-ground voltage rises to the line voltage , posing a threat to equipment insulation. If not promptly addressed, it may develop into a two-phase short circuit, and arc grounding can also cause overvoltage throughout the entire system. Our company’s ZF-WXJ series low-current system grounding microcomputer line selection device uses a 16-bit single-chip microcomputer for analysis and judgment. Its principle utilizes the relationship between the “relative amplitude” and “relative phase” of the zero-sequence current when a single-phase ground fault occurs in a low-current system . This eliminates the “absolute setting value” concept of previous devices, thus overcoming misjudgments caused by variable system operating modes and small ground currents. When a single-phase ground fault occurs in the system, the fault line number can be quickly and accurately determined.
Device Features :
◆ Fast analysis speed. When a ground fault occurs on the tested line, the analysis result can be obtained within 1 second
. ◆ Automatically stores 12 levels of ground fault information and 20 levels of resonance information (when the detuning function is added)
. ◆ Optional voice alarm function directly reports the faulty line name for user convenience.
◆ The detuning function can be added to quickly eliminate ferromagnetic resonance and determine its frequency and amplitude
. ◆ Optional tripping function: When a single-phase ground fault occurs on the line and a trip is required, this device can close the trip output contact to drive the trip (contact capacity is DC 220V 5A)
. ◆ Adopts a large-screen LCD to directly display the grounding line number or line name in Chinese characters
. ◆ This device is suitable for 0.38kV to 66kV power systems with an ungrounded neutral point, grounded via an arc suppression coil, or grounded via a resistor . Whether it is metallic grounding or resistive grounding, it can accurately select the grounding line number without being restricted by the outgoing line form (overhead line or cable line).
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