DLY Adjustable Residual Current Device

DLY, Residual Current Relay application is the most important protection element protecting human life. While LV Surge Arrester products protect the electrical devices in the system, residual current relays protect human life in a possible leakage, and it is mandatory to be applied in all facilities in our country. The common problem of all facilities is that residual currents do not hold and human life is at risk. Therefore, facilities where residual current does not work correctly cannot obtain an installation conformity report and fall into the risky class at the legal level.

As Yılkomer, we bring a definitive solution to this problem of facilities. By conducting engineering, survey, and application studies, we put an end to the problems of residual current not holding in systems with the products of DLY, the world’s smartest relay unaffected by Harmonics, for which we carry out the country responsibility. We offer a definitive solution to the troubles of systems with toroidal application and relay. You can request a free demo by filling out the form at the end of the article regarding the subject.

With high-technology residual current relays;

1. You prevent unwanted situations such as fire that may occur due to electrical malfunction in your business.
2. You protect the lives of your employees against electrical leakages in your business.
3. You can eliminate production losses by ensuring that your business uses electrical energy uninterruptedly.

As stated in the electrical internal installation regulations of the Ministry of Labor and Social Security, residual current relays with 300 mA tripping current for fire protection in main distribution panels, and residual current relays with 30 mA tripping current for life protection in all sub-panels, equipment, sockets, motors, machines, and devices should be used together with a fuse. However, until today, it was not quite possible to comply with this regulation with many brands and models of residual current relays sold in the market. Because there is only one reason for the event we call leakage current. This reason is insulation fault. Or insulating materials with low insulation levels are used. Where there is an insulation fault, the leakage current rises to very high currents and even results such as visible arcs emerge. Otherwise, a situation called leakage current never occurs. What occurs are harmonic currents. Most of these harmonic currents do not return via the neutral line. Since their frequencies are high, they complete their circuit via the ground line by causing punctures in insulating materials. Therefore, residual current relays available in the market perceive these harmonic currents as leakage currents and trip. The voltage values of these harmonic currents are very low. That is, they do not even have the effect of a pen battery. But since the current amounts they create are greater than 30 milliamperes, they cause residual current relays to trip for no reason. Residual current relays, of which we are representatives, are never affected by harmonic and noise currents, unlike relays available in the market. It has a low-pass filter feature. That is, they never trip from interference and noise currents with high frequencies from 50 Hz to 2500 Hz. It is compatible with all grounding systems. (TT, TN-S, TN-C, TN-C-S, IT) It is a very sad situation that the relays you have purchased by paying very high costs until today do not respond to your demands. To avoid falling into this situation, you must definitely work with the right product. The characteristic of each machine is different from each other. Using the same type of residual current relay for every machine is the most common mistake made. Our experienced engineers determine the characteristic features and harmonic current levels of the machines with our high-technology devices during the survey. As a result of the determinations made, they make the right product selection for each machine.

Why Residual Current Relay, What is its History and Purpose of Use; When residual current relays are examined historically, it is seen that they started to be used 20-30 years ago in developed countries. In Turkey, its history is not very old.

However, due to the excessive increase in occupational accidents caused by electricity, residual current relays have become mandatory today. Even Occupational Safety Inspectors affiliated with the Ministry of Labor and Social Security have tightened their inspections. The rule they generally refer to is; Residual current relay for fire protection (300 mA) for main distribution panels, residual current relay for life protection (30 mA) for all machines, motors, devices, sockets, sub-panels, etc. must be installed together with a fuse. Also, they do not accept any residual current relay selected higher than 30 mA tripping current value for life protection. So why should there be a residual current relay; The purpose of the fuses, residual current relays, and Thermal magnetic circuit breakers we use in our business is to protect machines, people, and transmission lines. Otherwise, if you directly connect a machine with a label of 400 Volt, 10 Ampere, 50 Hz to a network with LV of 400 Volt, 50 Hz without these protection elements, it works healthily. None of these protection elements are needed for its healthy operation. This information is so important that let’s explain how this information is actually applied by us with an example. A new machine was purchased for Company A. The machine is placed in an area deemed appropriate in the company. Mr. Ahmet, the electrician of the machine, is called. Mr. Ahmet looks at the label information of the machine and sees these values. 400 Volt, 250 Ampere, 50 Hz. Mr. Ahmet calls his supplier and says, our 250 Ampere machine has arrived, we need 1 Thermal magnetic circuit breaker with a value of at least 250 Amperes. The supplier ships the 250 A thermal magnetic circuit breaker to Company A. Master Ahmet pulls the machine supply line referencing the distance and the current value of the machine, installs the thermal magnetic circuit breaker he bought at the beginning of the line, and commissions the machine. Let’s say good luck.

But let’s examine if it was really good. Let’s start by asking questions to Mr. Ahmet;

1. How were you sure that it would protect the machine, the line, and the machine operator when installing this magnetic circuit breaker on this machine and its line?
2. Did you know the line impedances between phases, between phases and neutral, and between phases and body (ground)?

Do these values not matter to you when selecting a switch?

3. Did you check the short circuit breaking current value of the Thermal magnetic circuit breaker you added to the machine and its line?

You can actually guess the answer. So, the results that an inappropriately selected protection element can create in this machine and business in the future;

1. In case of a short circuit that may occur between phases or between phases and the neutral line on the machine, a high short circuit current occurs. This short circuit current occurs according to the impedance value of the line between the lines. If this generated short circuit current remains below the short circuit breaking current of the Thermal magnetic circuit breaker, it means that this magnetic circuit breaker will not open and will not protect. Since the nominal current value and the related short circuit breaking currents of the thermal magnetic circuit breakers in the electrical installation preceding it are higher, they will not open either. Therefore, it means that the machine is actually directly connected to the LV part of the Transformer. The conductors drawn to the machine referencing the distance and the nominal current value of the machine cannot carry this very high short circuit current for a long time either, and very bad results such as fire will emerge.
2. The machine operator is at vital risk in a contact that may occur between the phases and the body on the machine. Because if we rank the impedance values of the conductors among themselves from small to large,

Impedance value between phases < Impedance value between phases and neutral < Impedance value between phases and ground line. Therefore, the switch that does not open in case of a short circuit between phases and a short circuit between phases and neutral will never trip between phases and the ground line. As a result, in case of a short circuit, a closed circuit is formed between the body part contacted by the operator who has contact with the ground line (with the machine body) and the transformer. According to the resistance of this closed circuit, a current flow occurs on his body. Therefore, vital risk is inevitable for a human being caught in high electric current.

3. Most of us know grounding measurement methods. By driving a stake or without driving any stake with new generation devices

We can easily measure the grounding transition resistance value. In both methods, we do not separate the point we will measure from the grounding line. Therefore, the value we measure is not only the transition resistance value of that point. It is the parallel equivalent transition resistance value of every point that has contact with the grounding line.

That is, even a single point leaving this closed parallel ring network means an increase in the equivalent resistance. That is, it means a decrease in the short circuit current that may occur between the phases and the ground line. Even if magnetic switches and fuses are selected appropriately today, a switch or fuse whose tripping current value is selected appropriately today may not be appropriate tomorrow due to the fact that ground lines are greatly affected by physical conditions and additions and removals to the ground ring network are made very frequently every day. In summary, choosing magnetic switches and fuses as life protection equipment means taking this risk. Also, conformity tests of fuses and thermal magnetic circuit breakers are performed in machine panels. That is, it is done from the end point of the supply cable reaching the machine panel, and the measured impedance values are taken from this point. Energy is carried to other electrical zones on the machine with conductors of much lower cross-sections than the machine supply conductor. Therefore, the conductor with a small cross-section where energy is carried and a large resistance value will reduce the short circuit current since it increases the resistance in a phase-ground short circuit that may occur in the region where it is carried. Therefore, it is inevitable that the fuse or thermal magnetic circuit breaker protecting up to the machine panel will remain ineffective in leakage currents that may occur in many parts of the machine. The machine operator faces vital risk in this leakage current situation. In summary; Since the tripping currents of the residual current relay are in values too small to compare with fuses and magnetic switches, the residual current relay really saves lives. It protects life and property safety. It prevents unwanted bad situations such as fire.

Grounding; having residual current relays in the electrical system is not enough alone. Because residual current relays protect against leakage currents. Protection against contact voltage is not sufficient either. If 50 Volts is accepted as the dangerous voltage limit, in a machine with a residual current relay that has a 30 milliampere adjustment stage and trips at a tripping current value of 25 mA, 50 Volts / 25 milliamperes: 2 kohms. In short, if the closed-circuit impedance value we complete with the contacted point without a grounding line is greater than 2 kohms, it means that the relay will not open. Because 25 mA current will not flow from the closed circuit in which our body is located. The residual current will not be able to see this value, but based on the formula Contact voltage = Residual current value X closed circuit impedance, the contact voltage value will exceed 50 Volts. Therefore, electric shock by contact voltage will occur. In summary, the grounding line and residual current relay must be installed together. Residual Current Relays from Past to Present; When residual current relays used in the past are examined (in the picture above), it is seen that the tripping current values in many of them are adjusted in kohms, not in mA in the adjustment part. Actually, the method was quite effective and correct. For example, for a relay set to 11 kohms, 230/11kohm: It meant that it would trip when a tripping current of 20 mA occurred. However, in today’s technology, electronic devices that renew themselves every day pollute the electricity network at the same rate. Harmonic currents are an example of this. At the same time, equipment with low-quality insulation used in the electrical installation of machines prevents the healthy operation of relays working according to ohm adjustment. Especially because high-frequency harmonic currents easily puncture this insulation level, ohm-adjusted relays do not work healthily. The only way to counter these harmonic currents is to work with a product that separates harmonic currents from real leakage currents. Our experienced engineers determine the characteristic features and harmonic current levels of the machines with our high-technology devices during the survey. As a result of the determinations made, they make the right product selection for each machine.

As Yılkomer, we offer definitive solutions to your leakage current problems in your facilities. We protect your devices with LV Surge Arrester and take human life under protection with Residual Current relay.

Don’t forget Yılkomer ‘Protects Your Values’

DLY ADJUSTABLE RESIDUAL CURRENT RELAY PRODUCT CATALOGS; Residual current relay and toroid application Adjustable Residual Current Relay

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