It has been identified that some customers are experiencing failures of the 4-20mA circuit in our discrete EL relays. The fault has no impact on the relay’s trip function capability, which remains fully functional as designed. The fault is unveiled as an incorrect 4-20mA output regulation. The 4-20mA output is provided for remote monitoring of the effective EL current being detected by the relay.
Ampcontrol has received reports of a customer experiencing nuisance EFLO trips on new IPD 11kV EFLO equipment. Upon inspection of hardware and investigation, Ampcontrol was able to identify that the environmental conditions subjected to the hardware as the root cause of the nuisance tripping.
The ELV-PRO relay is a successor to the VSD-Guard, a premium Earth Leakage Relay providing users with a greater visibility and insight into the earth leakage currents within their system. In recent months a number of concerns have been raised regarding the relay experiencing nuisance tripping. The concerns identified with the product do not prevent the ELV-PRO detecting Earth Leakage faults; rather users may experience nuisance tripping. The relay does not present a safety risk with all trips / failures resulting in a safe failure condition.
The function of the earth continuity system is to enable SAFE and RELIABLE operation of reticulated mining equipment by ensuring the presence of an adequate earth connection. Earth continuity is typically required in applications where there is a fundamental reliance on the earth return impedance for the electrical safety of the operating equipment.
IPD to OCS protection system feature differences.
Ampcontrol has recently been made aware of a condition that causes the ELD V3 and ELV V2 relays to power up into a tripped state. The trip is related to the internal charge of the super-capacitor. The issue may cause delayed power up of equipment as a reset will be required if a trip occurs.
The cause of this trip is not a safety concern nor will it pose any risks to operations experiencing this condition. The trip was detected during the commissioning stage where the equipment was undergoing repetitive power cycles.
If your installation is experiencing nuisance tripping due to DC offset sources, and you are not required to use Earth Continuity Protection for touch potential safety, then the following application note may be a suitable solution. The ECM3 Earth Continuity Relay utilises a DC sense signal to determine the Pilot Series and Shunt Resistance. In some applications where the relay is exposed to DC offset sources (i.e. when exposed to a cathodically protected wharf or pontoon to fight against corrosion), the applied DC source can interfere with the relay’s sensing ability.
The Ampcontrol ELM V2 earth leakage relay has been designed and approved for use on earth fault limited systems providing earth leakage protection (earth fault protection). The relay is also suitable for other applications where equipment or system earth leakage protection is required.
The Ampcontrol ELD V3 earth leakage relay has been designed and approved for use on earth fault limited systems, namely coal mining applications, providing earth leakage protection (earth fault protection) as per AS/NZS 2081:2011. The relay is also suitable for other applications where equipment or system earth leakage protection is required.
The Ampcontrol ELM V2 Earth Leakage Relay is electronic in design and is based on microprocessor technology. The earth fault current is measured using a toroid, with the trip time and trip threshold being able to be independently adjusted using selectors on the relay fascia. When a fault occurs and the trip level and time delay is exceeded the relay‟s trip function is activated. A trip will de-energise the trip contacts connected in the system control circuit. The trip condition 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 fascia of the relay.