Earth and Short Circuit Fault Indicator

Earth and Short Circuit Fault Indicator

General Description
The earth and short circuitfault indicator is an instrument fordetecting short circuit and earth faults. This fault indicator is used in eachloop of medium voltage radial networks. In order to avoid serious failurehappening to distribution power network, especially in the network where lotsof ring main unit with loadbreak switch were used,the upper level system must be tripped within the set time when short circuitor earth fault occurs in the lower level. When tripping andbreaking happens, the whole network subjected to the upper level will be poweroff. Our earth and short circuit fault indicator canlocate and indicate the fault section so that the operator can find and tripthe fault section quickly according to the alarm signal; this will not onlysave a lot of working time, but also shorten the system interruption durationand range of power outage.

Structure andComponent
3pcsof short circuit sensors for each phase cable
1pcs ofearth fault sensor for three-phase cable
1pcs ofindicating unit, which is connected with sensors bycables or optical fiber and is incorporated in a wholly sealed plastic housingto gather with the electronics for time reset and trip setting.

Application
The CEE earth and short circuit fault indicators offer three basic types: cableshort circuit fault indicator, overhead short circuit fault indicator and earthand short circuit fault indicator. The cable type isused in pad-mounted transformer, switchgear power cable connection pillar andetc, and the overhead type is used in outdooroverhead power lines.

Faults Indication
1. Shortcircuit with one LED for each phase on the panel
2. Earth fault—with one LED on the panel
3. Thefault status can be displayed on the panel or indicated remotely through remotesign contact.

Function
1. The sensorsare used to detect the load current and earth current respectively. A thresholdlevel electronic adjusts the trip level for earth fault and short circuit. Whenthe current exceeds the pre-adjusted threshold level, an impulse is sent to theindicating unit.  And then the respective LED is activated and starts toblink.
2. Minimumpulse current adjustment: the indicating unit is equipped with a minimumimpulse threshold current used to evaluate the pulse current from the sensor.If the pulse current is less than the threshold level, no fault will beindicated. And if the pulse current  is higher  than  the  threshold level, an earth fault or shortcircuit fault will be indicated.
3. Theequipment has the function of inrush restraint, which avoids the wrongindication by the switching on/off operation.
4. Connectionterminal with a cover is to avoid short circuit and damage by dusts and dew

Reset
1. Automatictime reset: A time element controls the indication and resets it after thepre-adjust time (Values between 2-48h areselectable at plant).
2. Manualreset: Reset the indication by the TEST/RESET button on the panel (Press forRESET, press and remain 5 seconds for TEST)

Specifications ofShort Circuit Fault Indicator
Voltageclass: ≤35kV
Operatingcurrent: 10-600A
Tripcurrent level: 100A
Automaticreset time: 2, 4, 6, 8, 12, 24h optional
Resetcurrent: ≥10A
Operatingtemperature:  -40℃- 60℃
Cablediameter: φ5mm-φ30mm for cabletype, φ5mm-φ35mm for overhead type

Specifications ofEarth and Short Circuit Fault Indicator
EarthFault warning current: 3-200amp ±10%
Shortcircuit warning current: 150-1500amp±10%
Ambientcondition: -18℃- 60℃
Powersource: 3.6lithium battery (duration more than 5 years)
Batterylow voltage warning level: ≤2.93V
Automaticreset time: 1, 4, 8, 12, 16, 24, 48hr (optional)
IPCode: IP54
Outputcapacity of transfer relay: 220VAC/0.3A,or 30VDC/1A
NormalConsuming current: 10μA
Operatingcurrent of indicator: ≤0.8mA
Maxwithstand current of short circuit current sensor: 20kA at 3S
Earthfault sensor is used on three-core cable, outer diameter:≤110mm
Shortcircuit sensor is used on single-core cable, outer diameter: 35mm
Dimensionof the indicating unit (Length*Height*Depth): 94mm*48mm*88mm
Dimensionof the mounting hole on the panel (Length*Height): 90.5mm*42.5mm

Packaging
Each indicatorhas individual box.

As a earth and short circuit fault indicator manufacturer, CEE provides acomprehensive range of medium voltage power distribution equipment, includingbushing surge arrester, separable connector, overhead short circuit faultindicator, to name a few. Our company has received the ISO9001 and ISO14001certificates, and our products have been CCC certified. We are located in Fuzhou City, FujianProvince, which provides us with easy access to convenient sea, land and airtransportation.