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Industrial Leakage Current Protection With Grup Arge Engineering: KAR and TAT Series
Ensuring the safety of electrical installations is of utmost importance in both human safety and system sustainability. Leakage current protection systems, the building block of safety in these systems, provide a crucial and necessary infrastructure in a wide range of areas, from industrial plants to commercial buildings. The Current Leakage Relay (KAR) and Torodial Current Transformers (TAT) series, developed by Grup Arge, allows you to safely and precisely build this infrastructure.
You can find how leakage current protection systems work, the technical benefits of Grup Arge products, and the critical points to consider when building an electrical infrastructure.
What is a Leakage Current? How does it Occur?
In an ideal electrical infrastructure, the current comes into a device through the phase line and goes back to the system through the neutral line. In this ideal scenario, there would be no differences between the phase line and the neutral line, and the currents are equal.
However, if there is a problem in the conductors or insulators, some of the current that grounds through the neutral line goes through the ground by other conductors, such as wet floors or the human body.
Here are the main reasons why the current goes out of route to the ground:
Insulation Faults: Wear and tear in the protective layer covering the cables or melting of the layers, caused by overheating.
Physical Damage: Cables getting crushed, eaten by rodents or the contact of live wires with the metal surface of the device due to impact.
Humidity or Contact with Water: Contact of the wires with water causing an alternative route for grounding due to the conducting nature of water.
Aging and Wear: Extended use of electrical components causing their insulation to gradually worsen throughout the years, and allowing current through gaps starting from microscopical gaps.
The Risks Caused By Leakage Current
Unchecked leakage current can cause two major problems in electrical installations:
Threats to Human Life: The leakage, going through the metal shell of the device, can get grounded through the human body and cause electrical shocks. The reference point for human safety is 30 mA, and leaks over this point can cause fatal accidents.
Risk of Fire: The consistent points of leakage causes serious heat over time. The reference point to protect the facility from a risk of fire is 300 mA, and this amount of leakage can cause fires.
The Working Principles of Leakage Current Protection System
The leakage current protection system essentially consists of two components: a Toroidal Current Transformer that detects the leakage current, and a leakage current relay that processes the information and cuts the circuit.
- Toroidal current transformers detect the phase and neutral lines and generate a magnetic field, inducing voltage in the secondary coil.
- The currents that go in and out are equal in an ideal system. However, differences between the phase and neutral lines indicate a leakage current in the system.
- The toroidal transformer detects this difference and activates the protection mechanism.
- The leakage current relay measures the leakage current difference generated by the toroidal transformer and activates the circuit breaker.
Grup Arge Toroidal Leakage Current Relays (KAR01 and KAR11)
The Grup Arge Toroidal Leakage Current Relays can run between a leakage current of 30 mA to 30 A, and provides a turn-on delay time between 0 and 5 seconds. The leakage current levels of 25, 50 and 75 percent can easily be seen on the relay thanks to its LED system.
The KAR11 Series, specifically designed for tough industrial settings, has an advanced harmonic filter.
- Thanks to this harmonic filter, the device doesn’t get affected by the harmonic signals formed in the line.
- It also prevents a faulty opening of the relay in the electronic panels that are connected to devices causing high harmonics, such as arc furnaces, uninterruptible power supplies and welding machines.
- Because of these features, KAR11 can be safely used in places that have harmonics.
Front view of KAR01-KAR11 Toroidal Leakage Current Relay
High Precision: Toroidal Current Transformers (TAT Series)
Toroidal Current Transformers are highly precise measuring devices, acting as the eye of leakage current relays.
- The devices can withstand high resistances thanks to the toroid design.
- It minimizes the electromagnetic parasites.
- Maximizes the precision of the current measurement.
- The product has circular models that have a radius of 40 mm, 80 mm, 160 mm, 210mm and 300 mm to accommodate the needs of different installments.
- There are also rectangular models, with sizes of 280 x 115 mm and 470 x 160 mm, for wider cable groups.
Important Note: The toroidal current transformers are highly sensitive measurement devices. Because of that, the protection of its physical integrity is of utmost importance during logistics, storing and assembly. Events such as dropping, impacts, high pressure or misassembly can cause microscopic damage in the magnetic core and the second coil inside the toroid.
Applications of Leakage Current Relays
- Sockets and Lighting Lines: It is used with the sensitivity of 30 mA, to protect human life in electrical panels, and wet areas such as kitchens.
- Production Lines with High Harmonics: There could be faulty openings because of complicated signals in lines with high harmonics, such as arc furnaces, uninterruptible power supplies and welding machines.
- Fire Protection Points: 300 mA relays are used in plants or main electrical panels of buildings to prevent the arc and overheating that is caused by isolation faults.
- Hospitals and Health Centers: The relays are used to provide consistent safety and high precision in extensive care units and operating rooms.
- Shopping Malls and Offices: A gradual protection is provided in high human density buildings for illumination, air conditioning and safety of the sockets.
Things to Consider During Assembly and Installation
In order for a leakage current protection relay to work properly, the assembly rules should be followed precisely. These things should be considered in the installment infrastructure:
- Mandatory Use: KAR01 and KAR11 devices must be used with Grup Arge branded TAT series toroidal current transformers to avoid compatibility issues. Using them with current transformers of different conversion ratios is strongly discouraged, as it may lead to life-threatening dangers.
- Cable Setup: All the phase cables and (if present) the neutral cable should be passed through the toroidal transformer.
- Isolation of the Ground Line: The ground line mustn’t be passed through the toroidal transformer.
- Centering: The cables should be as close as possible to the middle of the toroidal current transformer to increase the precision of the measurement.
- Volume of the Cables: The total volume of the phase and neutral lines that goes through the toroid transformer should be less than the inside volume of the toroid transformer. For the most precise measurement, the inside radius of the toroid transformer should be at least 1.5 times bigger than the total cable radius size.
Besides the choice of equipment, these engineering details are important to provide maximum security, highest longevity and up-to-standards infrastructure in your facility.
Conclusion: Grup Arge Assurance in Electrical Safety
Guaranteeing safety of both humans and environment is only possible by a combination of high quality equipment, precise engineering and implementation processes. It is of utmost importance to build your infrastructure with high quality and safe equipment in order to protect humans and facilities from unforeseen risks. You can safely use KAR series toroidal leakage current relays and TAT series Toroidal current transformers, developed by Grup Arge, to provide maximum safety and security in your facilities.