Earth Fault Indicator EFI-BLZ-50 User Manual

EFI-BLZ-50

CONTENTS

SAFETY NOTICE ....................................................................................3

1 OVERVIEW ......................................................................................4

2 DESCRIPTION.................................................................................5

2.1 CONTROL UNIT............................................................................5 2.2 CT SENSOR..................................................................................6

2.2.1 CT Sensor Selection............................................................6 2.3 REMOTE INDICATOR: (OPTIONAL) ...............................................8 2.4 AUX. RELAY: (OPTIONAL) ...........................................................9 2.5 MANUAL TEST/RESET BUTTON ...................................................9 2.6 AUTOMATIC RESET PERIOD SELECTION.......................................9

3 OPERATION. .................................................................................11

3.1 EARTH FAULT DETECTION.........................................................11 3.2 TRIPPED STATE RESETTING .......................................................12

4 TESTING.........................................................................................12

5 SPECIFICATIONS.........................................................................13

5.1 TECHNICAL DATA......................................................................13 5.2 MECHANICAL DATA : .............................................................14

6 ORDERING ....................................................................................15

7 WARRANTY...................................................................................17

EFI-BLZ-50

Safety Notice

Review the following safety precautions to avoid injury and prevent damage to this product or any products connected to it. To avoid potential hazard, use this product only as specified. This equipment contains voltages that may be as high as 415 volts. Electrical shock can cause serious or fatal injury.

This unit may also be connected to other equipment that may have high voltages. Improper use can cause serious or fatal injury.

PRECAUTIONS

WARNING: Under certain fault conditions, high voltages can be brought into the earth fault indicator enclosure through the CT, remote indicator LED, or the Aux. Relay cables. All parts within the enclosure should be handled as if carrying dangerous voltages.

WARNING: Use extreme caution during the installation and use of the EFI product as high voltages and currents may be present in the circuit.

• Ensure that the CT sensor is installed on the screened part of the HV cablesystem and is at earth potential.

• This product must be installed and used only by qualified personnel that arefamiliar with practicing applicable safety precautions.

• The EFI product should not be installed on live conductors.• Wear necessary protective clothing and gloves as required.• Always inspect the CT sensor, remote indicator and all leads for damage before

using the product.• Do not use the product if damaged.

EFI-BLZ-50

1 Overview EFI-BLZ-50 is one of a family of Earth Fault Indicator products that is designed to assist in the rapid location and isolation of faults on high voltage networks (1 – 36kV) in single-sided-feed or open ring main systems. When an asymmetrical current greater than 50A in a 3 phase cable is detected an earth fault is indicated by means of a flashing LED (Light Emitting Diode) indicator.

EFI-BLZ-50 has a current sensor fixed around the three phases of the cable system that detects a current imbalance due to an earth fault. An earth fault trip is indicated by an LED indicator on the unit, with a second Remote Indicator (optional) available together with an auxiliary relay contact for connection to other systems (optional). In an open ring network the path of the fault current from the feeding point to the fault location is marked by the triggered EFI’s. The defective conductor segment is located between the last EFI that has been triggered and the first EFI, which is still inactive.

The main features of the EFI-BLZ-50 product include:

• Powered from 3.6V ½ AA Lithium Battery• LED Primary indicator.• Automatic reset of fault state on user selectable 4 hour or 8 hour period.• Manual reset of flashing LED by Test/Reset button on the front panel.• CT100 Current Sensor (standard)• CT150 Current Sensor (optional)• CT300 Current Sensor (optional)• LED Remote indicator. (optional)• Aux. Relay contact for remote alarm generation. (optional)• Rugged design suitable for outdoor use• ISO9001:2000 based Quality Assurance

EFI-BLZ-50

Battery Power Supply

LED IndicatorTest/Reset Button

EFI Enclosure

Aux Relay Connector Cable

Glands

Remote Indicator Connector

Mounting screw holes

CT Connector

2 Description

The EFI-BLZ consists of the following components:

2.1 Control Unit

This contains the necessary monitoring and detection circuits for detecting and validating an earth fault as well as activating the fault indicators.

The control unit is normally mounted onto a vertical surface. When the cover is removed, mounting screw holes are exposed for use in fixing the indicating unit to a surface. Four two-way screw terminals inside the unit provide a means of connecting Mains Supply, Remote Indicator, Aux. Relay and CT to the unit. These cables are fed through the cable glands (M12) provided and secured in place using the locking nut. When the cover and cable glands are tightened firmly the enclosure provides IP65 protection.

Figure 1.0 EFI- Control Unit

The EFI-BLZ is powered by a replaceable 3.6V 1/2 AA Lithium battery which has a shelf life of over 10 years. During normal monitoring operations the power drawn by the device is so low that it approaches the self-discharge rate of the battery itself. It is only when an earth fault is detected (or

EFI-BLZ-50

under test mode) that significant current is consumed. Even then, the power consumption is still very economical and can remain active driving the primary LED indicator for over 1000 hours continuously. The status of the battery can be checked by manually testing the unit. (See Section 2.5).

The primary indication on the EFI-BLZ is an LED based indicator that flashes at a rate of 1Hz when a fault is detected. The unit is programmed to trip at a nominal earth fault current of 50A (other trip values can be supplied on request) and remains tripped until manually reset by pressing the Test/Reset button or is automatically reset after a user selectable 4 hour or 8 hour period. The unit is designed to operate in the harsh environment of medium voltage networks (1 – 36kV).

A link option is provided to select the period after which the unit automatically resets following the detection of an earth fault. This provides the option of a 4 hour (default) or 8 hour activation period (other periods can be supplied on request), following which the unit will automatically reset.

2.2 CT Sensor

The EFI-BLZ CT sensor comprises of a flexible iron-core belt with a magnetic field pickup coil attached. The belt is fitted around the three-phase cable system being monitored and works on the principle of core-balance current sensing. Under normal operating conditions the magnetic flux produced by the three phase currents sums to zero resulting in the pickup coil on the iron-core generating no voltage output. When an earth fault occurs the flux will be non-zero resulting in a voltage proportional to the magnitude of the earth fault being generated by the pickup coil. The CT sensor has no exposed iron parts and is completely encapsulated in corrosion proof material. The CT is supplied with a 3 meter length cable as standard.

2.2.1 CT Sensor Selection The EFI-BLZ comes with the CT100 sensor connected as standard. A CT150 sensor is also available but must be ordered separately, both of which are suitable for multi-core cable systems. A larger sensor CT300 is available for single core cable systems and must be ordered separately.

EFI-BLZ-50

2.2.1.1 Multi-Core Cable System For multi-core cable systems the CT100 (or CT150) sensor is mounted on the screened part of the cable below the strip-back point of the cable as shown in Figure 2.0. The centre cable-tie of the CT sensor is used to secure the sensor firmly on the cable. The flexible iron core of the sensor must be wrapped in a closed circle and pulled tight with the second cable-tie, as far as is possible. Care should be taken to ensure that the sensor is mounted on the screened part of the cable. The screen of the cable should be turned back underneath the core and terminated to earth as shown in Figure 2.0. The third cable tie (if fitted) must be closed, to ensure the end of the CT is properly aligned. The end of the bands should be fitted neatly under itself. Care must be taken during this process, to ensure the CT is closed properly. Otherwise the accuracy of the trip level will be affected.

Figure 2.0 Mounting of CT100 sensor on Multi-Core Cable System

2.2.1.2 Single-Core Cable System For Single-core cable systems a larger CT300 sensor is used. The CT300 sensor is mounted on the screened part of the cable below the strip-back point of the cable as shown on Figure 2.1. The centre cable-tie of the CT is first used to secure the sensor on one of the cables. The flexible iron core of the sensor is then wrapped in a closed circle around all three cables and pulled tightly with the

EFI-BLZ-50

second cable-tie as far as is possible. Care should be taken to ensure that the sensor is mounted on the screened part of the cable. The screen of all three conductors should be turned back underneath the core and terminated to earth as shown in Figure 2.1. The third cable tie (if fitted) must be closed, to ensure the end of the CT is properly aligned. The end of the bands should be fitted neatly under itself. Care must be taken during this process, to ensure the CT is closed properly. Otherwise the accuracy of the trip level will be affected.

Figure 2.1 Mounting of CT300 Sensor on Single-Core Cable System

2.3 Remote Indicator: (Optional)

An LED based remote indicator can be fitted if required, and needs to be specified at time of order. A two-way screw terminal connector is provided on-board for connecting the remote indicator. During a fault condition the remote indicator will flash at a rate of about 1Hz. The remote indicator is mounted inside an M12 Nylon bolt which is weather-proof and corrosion proof, as shown in Figure 2.2 below. The remote indicator is supplied with a 3 meter length of cable as standard.

EFI-BLZ-50

Figure 2.2 Remote Indicator

2.4 Aux. Relay: (Optional)

Additional signalling can be provided by an on-board latching relay, if specified at time of order. The Aux. Relay provides a potential-free, normally-open contact for healthy state monitoring. A tripped state will latch the relay into a set position (closed). The latching relay retains its last set state even if the battery fails. The Aux. Relay is supplied with a 2 meter length of cable as standard.

2.5 Manual Test/Reset Button

The control unit includes a manual Test/Reset pushbutton on the front panel. This button is used to both test the system and also to manually reset an earth fault state.

EFI-BLZ-50

To test the system the Test/Reset button must be pressed for a period of 3 seconds, to avoid accidental operation. The state of the battery is first indicated on LED indicators. If the battery is in a healthy state the LED indicator will flash rapidly at 10Hz for a few seconds and then commence flashing at its normal rate of 1Hz. If the battery is not in a healthy state the LED indicator will commence to flash at its normal 1Hz rate or will not flash at all, in which case it should be replaced to ensure safe operation of the unit. The device is protected against reverse polarity connection.

This test button sequence will also activate the Aux. Relay contacts (closed), if connected, and the remote LED indicator (if connected) will also flash at the same rate as the primary LED indicator of 1Hz.

This test state will continue for a period of 60 seconds or until the test button is pressed again to terminate test mode. To terminate a test, the Test/Reset button need only be pressed for a brief period. This will reset the Aux. Relay to the reset (opened) position and stop flashing of both the primary LED indicator and the remote indicator, if fitted.

The Test/Reset button is also used to manually reset the unit from a tripped (Earth Fault) state. To do this the Test/Reset button must be pressed for 3 seconds. This will reset the Aux. Relay to the reset (opened) position and stop flashing of both the primary LED indicator and the remote indicator, if fitted.

2.6 Automatic Reset Period Selection

To select the automatic reset period of the unit following the detection of an earth fault a 2-way link option is provided inside the unit. This link option is accessed by removing the front cover of the unit and is clearly marked ‘Reset 8H 4H’. This permits the selection of either a 4-hour or 8-hour automatic reset period.

To select 4-hour automatic reset: (Factory Default Setting) Move the link to the 2 pins located beside the 4H mark.

To select 8-hour automatic reset: Move the link to the 2 pins located beside the 8H mark.

Other automatic reset time periods can be supplied on request.

EFI-BLZ-50

3 Operation. During normal operation the device continuously monitors the output of the current sensor (CT100, CT150 or CT300) for an earth fault signal as well as the Test/Reset button for a unit test request.

3.1 Earth Fault Detection

In the event of an earth fault occurring, the CT sensor will transmit a voltage that is proportional to the measured current. The onboard circuitry analyses the voltage produced to determine that it is a valid earth fault signal as opposed to a transient spike or glitch. The minimum fault duration is 2.5 cycles (50mSec for 50Hz and 40mSec for 60Hz). All current spikes and glitches are ignored. For fault currents in excess of 50A a limiting circuit inside the control unit clamps the output voltage of the CT sensor to a safe operating voltage for the unit

When a valid fault current is detected, the Aux. Relay is latched into a tripped position (closed) and both the primary LED indicator and remote LED indicator (if fitted) will commence flashing at a rate of about 1Hz. The EFI-BLZ will remain in a tripped state until automatically reset after the user selectable 4 hour or 8 hour period or is manually reset using the Test/Reset button.

EFI-BLZ-50

3.2 Tripped State Resetting

Resetting of a tripped state can be done manually or automatically.

Automatic Reset A user selectable 4 hour or 8 hour link option is provided for selecting the period after which the unit automatically resets following the detection of an earth fault. Once this period has expired the unit will latch the Aux. Relay to a reset position (open) and terminate flashing of the primary LED indicator and remote LED indicator, if fitted.

Manual Reset The Test/Reset button is used to manually reset the unit from a tripped state prior to mains being restored. To do this the Test/Reset button must be pressed for a period of 3 seconds to avoid accidental resets.

In both cases the unit returns to low power mode and continues to monitor for earth faults.

4 Testing

To check the trip current level of the EFI-BLZ the following test should be

conducted.

1. Ensure that the battery voltage is healthy by using the Test/Reset buttonto check its status.

2. Generate a fault current less that 45A in the current carrying conductorrunning through the CT sensor. This should not trip the unit.

3. Generate a fault current greater than 55A for a period of 1 second. Thisshould trip the unit.

EFI-BLZ-50

4. Remove the fault current and press the Test/Reset button for more than3 seconds. This will reset the unit from tripped mode.

5 Specifications

5.1 Technical Data

Network voltage range: 1-36kV AC Trip current: 50A ±10% Minimum fault duration: 2.5 cycles (50ms @ 50Hz / 40ms @

60Hz) Fault current withstand: 25kA for 1s Primary Indication: High intensity Red LED Flash rate: 1Hz nominal Flash duration: 1000 hours continuous flashing.

(500 hours if Remote Indicator is fitted.) Reset of Fault: Automatic – 4 hour or 8 hour selectable

or Manual -Test/Reset pushbutton Operating temperature range: -20ºC to 70ºC Operating humidity range: 0 – 100% RH

Remote indicator (optional) Type: High Intensity Red LED Flash rate: 1Hz nominal Flash duration (no mains): 500 hours continuous flashing

Auxiliary Relay (optional) Type: Latching, N/O on reset Max Switching Voltage 250VAC, 220VDC Max Continuous Current 2A Maximum switching Capacity 60W Cable length standard*: 2m Lead type: 2-core, 0.5mm sq double insulated

Battery Type: 3.6V Lithium ½ AA 850mAH Flashing Life: 1000 Hours

(500 hours with Remote Indicator)

EFI-BLZ-50

5.2 Mechanical Data :

Control Unit Dimensions: 115mm × 65mm × 40m excluding cable

glands Material: ABS grey, ingress of dust and moisture

protection IP65 Mounting: Surface-mounting, two 4mm holes Cable gland size: M12; cable diameter range 3-6.5mm Weight: 200g

CT sensor CT100 (Shipped as standard) 100mm diameter (Multi-core cables) CT150 (Ordered separately): 150mm diameter (Multi-core cables) CT300 (Ordered separately): 300mm × 100mm

(Single-core cables) Mounting: Releasable cable-ties Cable length standard*: 3m Lead type: 2-core, 0.5mm sq double insulated Weight: 145g

Remote indicator Dimensions: M12 Hex head Bolt 50mm long Material: Nylon Lead length standard*: 3m Lead type: 2-core, 0.5mm sq double insulated Protection: IP65 Weight: 250g.

* Extra length cable can be obtained at extra cost, if requested at order.

EFI-BLZ-50

Ordering

Earth Fault Indicator ordering information

First Group Product Range EFI Earth Fault Indicator

Second Group 1st Char: Power Source M Mains Powered B Battery Powered C CT powered

2nd Char: Indicator Type F Flag L LED

3rd Char: Glands Z Cable Glands fitted Third Group 1st Char: Remote indicator fitted R Remote LED Indicator

2nd Char: Cable length in metres 3 3 meters

Fourth Group 1st Char: Aux. Relay fitted A Aux. Relay fitted 2nd Char: Cable length in metres 2 2 meters

Fifth Group 1st Char: Mains cable fitted M Mains cable 2nd Char: Cable length in metres 3 3 meters

Sixth Group Nominal trip current in Amps 50 50 Amps trip level

Seventh Group 1st Five Char: Current Transformer (CT) CT100

Up to 100 mm dia. (multi-core cables)

CT150 Up to 150mm dia. (multi-core cables)

CT300 300mm × 100mm (single-core cables)

6&7th Char: Cable length in metres 3 3 meters

For example:

Notes:

• The remote indicator & Aux. Relay are optional component.

• The EFI unit does not ship with any leads for the mains voltage input or theAux. relay output, unless stated at time of order.

EFI-BLZ-R2-A2-M3-50-CT150.3

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• The unused cable-glands ship with a rubber stopper inserted to maintainsealing integrity.

• The EFI unit ships in a brown corrugated cardboard box.

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6 Warranty This product is warranted to be free from defects in material and workmanship for a period of twelve months (12) from the date of shipment. Correction shall be in the form of repair or replacement of the defective items or components, freight paid by the customer both ways. Such correction shall constitute a fulfillment of all TransTechnical liabilities in respect to said items and components. In no event shall TransTechnical be liable for consequential damage.

No other warranties: To the maximum extent permitted by applicable law in the Republic of Ireland, TransTechnical disclaims all other warranties, either express or implied, including but not limited to implied warranties of merchantability and fitness for a particular purpose, with respect to the EFI product and accompanying product manual.

Disclaimer: To the maximum extent permitted by the laws applicable in the Republic of Ireland, in no event shall be liable to the user for any special, indirect, consequential or similar damages, including any lost profits or lost data arising out of the use or inability to use the product or documentation.

EFI-BLZ-50

TransTechnical Solutions

Unit F11, Roete 2450 Herman RoadMeadowdaleGermistonTel: +27 (0) 11 974 9671 Fax: +27 (0) 11 974 9653 Email: sales@ttsafrica.com Web: www.ttsafrica.com