Manual - Blue Electronics
Contents
1. 8 a Current 0 5A impedance imped earthing T 1 T Rer MUR E Ip Earth Current Path 00 Y TOHLNOOdIAV 0 8 07061 A1N3IW39NVHUV TIVH3N39 INNON ANY TANVd dsvo NOILdO ONILNNOW NIG Pav ao wss gt avo awl J 9865 95 670 6685 95 670 150 3116 0 3 AVG QvOH 052 FUSVOMAN 301440 191 042 000 NOV G11 Ald TOHLNOOdAV PIT Ald jevoudde samed pau sjuejuoo sii 10 ejouw 10 ped eq jou snw pue 2991 0 joefqns 5 pr1 Aid jonuooduiy 10 eui sureuje1 siu X SNOISN3WIG 13Z38 907805 ON LuVd 3SV8 TIVY 074 2 90780470 LuVd AV T3H 073 SALON v 66 x Wg 100119 NOILdO GSLNNOW T3NVd du du eram no SOO e PS cu 20 90 81 810 NYO2. ELD Earth Leakage Protection Relay 431203 1213 No copies of the information or drawings within this manual shall be made without the prior consent of Ampcontrol Designed and Manufactured in Australia by Ampcontrol Pty Limited ACN 000 915 542 Phone 02 4956 5899 Fax 02 4956 5985 www ampcontrol com au USER MANUAL E08846 ISSUE 1 8 03 04 ELD Manual Issue 1 E08846 080304 pdf Copyright Notice No part of this publication may be reproduced transmitted or transcribed into any language by any means without the express written permission of Ampcontrol Pty Ltd 250 Macquarie Road Warners Bay NSW 2282 Australia Disclaimer Ampcontrol Pty Ltd will make warranties as to the contents of this documentation and specifically disclaams any implied warranties or fitness for any particular purpose Ampcontrol further reserves the right to alter the specification of the system and or manual without obligation to notify any person or organisation of these changes Before You Begin We would like to take a moment to thank you for purchasing the ELD Earth Leakage Relay To become completely familiar with this equipment and to ensure correct operation we recommend that you take the time to read this user manual thoroughly ELD USER MANUAL ISSUE 1 CRN 4814 ELD USER MANUAL ISSUE 1 Protection Systems 1 The Need for Earth Leakage Protection
3. 1 2 Earth Leakage Systems 2 2 2 Methods of Earth leakage 2 20 20 2 2 3 Core Balance Protection 2 2 4 Series Neutral Protection 2 2 5 Earth Leakage Toroids 3 2 6 Selection 3 2 77 Installation Guidelines 3 ELD Earth Leakage Relay 31 44222222 4 3 2 Methods of Earth Leakage Protections ees ee ses 4 3 3 Testing Procedure 4 3 4 Totroids i 4 3 5 Mode of Operation 4 Specifications 5 Equipment List 5 Diagrams ELD Typical Installation Diagram 6 Core Balance System 7 Series Neutral System 8 Mounting Details esses 9 CONTENTS 1 Protection Systems Earthing of electrical equipment associated machinery and structures is a seemingly simple practice and is covered adequately by the various applicable sections of Australian Standards AS3000 or AS3007 However in the mining industry earthing is somewhat more complex than normal domestic or commercial applications and requires other factors to be taken into consideration particularly where trailing and or reeling cables supply mobile electrical equipment The protection systems are design
4. Switch Trip Level Time Delay Position mA mS 0 100 50 1 150 100 2 200 150 3 250 200 4 300 250 5 350 300 6 400 350 7 450 400 8 500 450 9 750 500 A 1000 750 B 1250 1000 1500 1500 1750 2000 2000 2500 F 2500 3000 Values marked with an asterisk should not be selected when there is a requirement to comply with AS2081 3 1988 Dimensions 47 Hx 77 Wx 116 Dmm 5 Equipment List E08405 ELD Earth Leakage Relay E08406 ELD DIN Rail Mounting Kit 08554 ELD ELC Adapter Kit 08554 ELD ELC F Adapter Kit C18058 Toroid 60mm ID C18059 Toroid 85mm ID C18057 112mm ID ELD USER MANUAL ISSUE 1 Typical Connection Diagram k Remie n T 1 ME am m Contacts in the Taser Gear on Fall Sale Link _ TIE EL 3 ae Currant ELD USER MANUAL ISSUE 1 CORE BALANCE EARTH LEAKAGE PROTECTION Supply Transformer Circuit Secondary Windings Breaker O Toroidal to mining Machine Impedance z J Test Pushbutton Earth to Machine ELD USER MANUAL ISSUE 1 SERIES NEUTRAL EARTH LEAKAGE PROTECTION t Main Breaker Contactor Supply Transformer Secondary Windings es ar pie OE Earth Fault Toroidal Cap Poshtutoh 1
5. protection the earth leakage system should be used in conjunction with the other protection systems covered by AS2081 The collective systems are designed to limit touch and step potentials The relay is also suitable for industry where equipment or system earth leakage protection is required The relay is not suitable for personal protection which requires trip levels ELD USER MANUAL ISSUE 1 of 20 30mA with instantaneous operation Refer AS3190 The ELD Relay continually monitors the toroid and if the connection is lost the relay will trip and flash the CT Fault LED 3 2 Methods of Earth Leakage Protection The ELD Relay is suitable for the two methods of protection used They are the Core Balance and Series Neutral earth leakage protection systems See previous section for details 3 3 Testing Procedure A test current is injected through the window of the toroid to test the operation of the relay See typical connection diagram Page 6 To reset the relay press the button located on the facia of the relay or provide an external normally open contact The reset button is also used to access the memory of the processor to view the maximum level of leakage since the previous trip A section of the bar graph will slow flash 2Hz indicating the peak level while the reset button is held closed and will continue to flash for 1 second after the reset button is released 3 4 Toroids The ELD Relay is designed for
6. the occurrence of an earth fault can be hazardous because it may cause a Frame to earth voltages dangerous to personnel b Electric arcing which may initiate an explosion or fire when arcing occurs in an underground mining operation The main purpose of earth fault protection is to safeguard personnel and electrical apparatus However it is found that relays designed to operate on fault limited systems are not suitable for personal protection i e users of portable drills grinders etc which require trip levels of 20 30mA with instantaneous operation Refer AS3190 The most common apparatus faults in mining applications are cable faults Cables are most susceptible to damage and are the major source of dangerous electrical incidents This applies particularly to the flexible trailing cables supplying power to mobile mining machines Cable construction is such as to provide every phase conductor with an individual conductor screen so that crushing would cause a low single phase to earth fault current The protective device such as an Ampcontrol ELD earth leakage relay would then isolate the cable and contain the sparking within the cable before a heavy short circuit current due to a phase to phase fault occurs Earth fault protection has been applied with considerable success in limiting faults and providing quick disconnection of electrical apparatus from the supply in the event of earth fault situations A definite
7. time operating characteristic is provided with adjustable trip sensitivity and time delay Time delay between protective units is introduced to allow the unit close to the fault to isolate the faulty circuit without causing the healthy part of the system to be de energised ELD USER MANUAL ISSUE 1 2 1 Earth Leakage Systems Desirable though it may be it is impractical to provide automatic protection against electrocution as a result of direct contact with a live conductor particularly where the electrical reticulation is exposed to a humid or damp atmosphere Table 1 indicates the current values affecting human beings Current mA Symptom 1 or less Causes no sensation not felt Sensation of shock not painful 1108 individual can let go at will as muscular control is not lost Painful shock individual can 8 to 15 let go at will as muscular control is not lost Painful shock muscular 15 to 20 control of adjacent muscles lost cannot let go Painful severe muscular contractions breathing difficult 50 to 100 Ventricular fibrillation a heart Possible condition that may result in 100to 200 death Certain Severe burns severe muscular contractions that are so severe that chest muscles clamp the 200 and over heart and stop it for the duration of the shock This prevents ventricular fibrillation Table 1 It will be seen from the foregoing table that the pass
8. use with Ampcontrol EL500S series Toroids They available with window sizes 60 85 112mm These allow trip settings from 100mA to 2 5A 3 5 Mode of Operation The relay can be operated in fail safe or non fail safe modes of operation Fail Safe Mode This mode is the default and preferred method where the relay drops out on fault or loss of power Power to the relay is from the line side of the isolating device or from an independent supply Non Fail Safe Mode In this mode of operation the relay picks up on fault This method should only be used when the supply to the relay is only available from the load side of the isolating device To select this mode link the NFS input terminals Note This mode of operation should only be used when there is not a requirement to comply with AS2081 3 1988 ELD USER MANUAL ISSUE 1 4 Specifications Relay Supply Volts 24 132V AC 20 185VDC 4 20mA Output The Loop Powered current output represents the leakage current as a percentage of the trip level 4mA gt 0 leakage 20mA gt 120 leakage 10096 17 33mA Maximum Loop Resistance Vs 10 x 50 where Vs must be greater than 10VDC and less than 30VDC Relay Contacts 1 N O 1 C O Rated at 5A 250V 100VA maximum Trip and Time Delay Settings Two separate rotary 16 position switches set the trip and time delay parameters of the relay
9. age of a current of as low as 15mA through the human body can cause loss of muscular control to the extent of preventing the recipient from disengaging from the live conductor Whereas a current in excess of 50mA is sufficient to produce a critical heart condition from which there is little or no chance of recovery It follows that as an effective safeguard against electrocution resulting from direct contact with a live conductor it would be necessary to introduce earth leakage protection designed to operate with a fault current below 15mA which in the majority of cases would be impractical The automatic protection of circuits is not intended to take the place of sound installation practice and the regular maintenance and testing of electrical apparatus Care must be taken in the selection and installation of all electrical equipment with due regard to its required duty and the conditions under which it may be called upon to operate Where automatic earth leakage protection has been installed it is essential that its operation be tested often and to facilitate this a means for testing is incorporated in all approved earth leakage relays 2 2 Methods of Earth Leakage Protection Earth Leakage Protection Relays for use in mining applications have to be designed and tested to AS2081 3 1988 for use on fault limited systems There are two methods of protection used They are the Core Balance and the Series Neutral earth leakage p
10. dures are not followed during installation nuisance tripping can result If for example we consider a single phase earth leakage system where active and neutral pass through a toroid then at all times currents in the two wires are equal and opposite so that the net current through the toroid is zero An ideal current transformer would have all of the flux from each wire contained in the core and so would accurately add the opposing fluxes to get a net result of zero A real current transformer has leakage fluxes That is a very small proportion of the total flux from each cable is not contained in the core but in the space outside it and as a result it may link some turns but not others depending on the positioning of the cables The effect of this is that a small output may be obtained from the toroid where none would arise if the device were ideal The size of the error may vary from toroids of the same type because of slight differences in the core and the symmetry of the winding Problems caused in this way increase as the toroid size increases as currents increase and symmetry decreases Nuisance tripping tends to occur when the total current rises such as when a large motor is started The following guidelines would help to avoid such problems 2 6 Toroid Selection 1 Select the smallest internal diameter toroid which will allow the cables to fit through Avoid very large toroids 200mm or toroids with square apertur
11. ed to provide touch and step potentials of 50 Volts or less when all the systems are used collectively It should be clearly understood that unless all four types of protection is incorporated in any design then personal protection touch and step potentials of 50V or less will need to be assessed by a competent person or authority The protection systems that cover coal and shale mines are detailed in AS2081 Part 1 to 5 Although these standards do not apply to metalliferous mining they are a good benchmark to follow Part 1 General requirements for electrical protection devices for use in coal and shale mines Earth Continuity monitoring devices Earth Leakage protection devices Lockout Earth fault devices before energisation Earth Fault Limitation impedance earthing Part 2 Part 3 Part 4 test Part 5 The above standards are not stand alone group and have been developed in co ordination with other standards being 1 AS1740 Underground mining substations 2 AS1802 AS1300 Reticulation trailing and reeling cables 3 AS1299 AS1300 Plugs adaptors couplers and receptacles 4 Internationally accepted voltage time effects on the human body based on IEC479 5 Installation in accordance with accepted State and Federal Regulations ELD USER MANUAL ISSUE 1 6 Equipment maintained in accordance with industry standards 2 The Need for Earth Leakage Protection Unless properly controlled
12. es 2 Only use approved toroids specified by Ampcontrol as these have been designed to minimise the problem 2 7 Toroid Installation Guidelines 1 Keep cables as close to the centre of the toroid as possible Do not tie them to one side of the toroid Remember to aim at symmetry 2 Do not bring the cables back past the toroid within one diameter of the toroid Trying to cram cables into a small space reduces symmetry and may lead to problems which are difficult to solve 3 Avoid placing the toroid near any device which produces magnetic fields This includes bus bars transformers or other cables Try to maintain several toroid diameters clearance 4 Many small cables tend to be worse than say three large ones Try to position the toroid in the circuit with this in mind 5 Toroids used for core balance earth leakage protection cannot have bus bars passed through the toroid To prevent possible nuisance tripping it is suggested that the conductor screen of the earth leakage toroid should be earthed one end only the relay end If both ends are earthed the possibility exists for the shield to become an earth loop having finite resistance and injecting noise into the toroid leads 3 ELD Earth Leakage Relay 3 1 Description The Ampcontrol ELD Earth Leakage Relay is electronic in design and is based on microprocessor technology The Relay uses a toroid to measure earth fault current definite time operating c
13. haracteristic is provided with adjustable trip sensitivity and time delay When a fault occurs and the trip level and time delay is exceeded the relay s trip function is activated operating the trip contacts connected in the system control circuit In Fail Safe Mode the trip is latched in non volatile memory and requires operation of the reset input to clear the trip condition An internal reset is also provided on the facia of the relay A ten segment LED bar graph indicates the of leakage level being detected This reading can be remotely monitored displayed using the 4 20mA Output of the Relay When the relay measures currents with frequencies much greater than 50Hz the bar graph LED fast flashes 5Hz instead of being steady Should the high frequency current persist until the time delay is exceeded the relay will trip and the Har Trip LED Harmonic Trip will be illuminated The ELD Earth Leakage Relay is housed in a stainless steel case and can be either DIN Rail mounted or Panel Mounted through a 68 x 38mm cut out When panel mounted the front of the ELD Relay is designed to provide IP 56 ingress protection It also provides provision to prevent unauthorised adjustment of the trip settings An internal switch mode power supply allows the ELD to operate from 24VAC to 132VAC or 20VDC to 185VDC The ELD Relay has been designed and tested to AS2081 3 1988 for use in mining on fault limited systems To ensure maximum
14. rotection systems The Core Balance relay performs the primary protection in an installation protecting the outlet supplying power to a machine In this application the time delay is set at instantaneous The neutral earth leakage relay is the back up relay of the installation and can have a time delay up to a maximum of 500mS 2 3 Core Balance Protection With this method the three phases are passed symmetrical through the toroid If there is no earth fault present the vector sum of the currents in a three phase supply is zero If current from any phase flows to earth the system becomes unbalanced The toroid produces an output which trips the relay A test current is injected through the window of the toroid to test the operation of the relay See typical circuit Page 7 2 4 Series Neutral Protection With this method the neutral is passed through the toroid An earth fault on any of the phase conductors causes an earth current which returns through the toroid to the star point of the transformer A test circuit can connect a test resistor between a phase and earth or inject a current through the toroid as previously described The ELD USER MANUAL ISSUE 1 test resistor to earth method is recommended with this type of protection as this test also proves the neutral to earth connection See typical circuit Page 8 2 5 Earth Leakage Toroids Toroids current transformers are not ideal devices and if correct proce
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