Webinar «Overvoltage limiters for the data transfer systems protection», page 2

— Testing by our laboratory. At first, we carry out mechanical tests, measure nominal electric parameters of our circuit and carry out pulse tests by using generators seen on the right. On the low left corner one can see the tests carried out by us in Bialystok University of Technology, the tests of resistance against high-energy pulses and the tests of destruction of protective circuits, because we need such information to specify it in the technical data.

— We always carry out the tests for low-current lines. According to IEC standard 61643-21 – low-voltage circuit surge protection devices, telecommunication and alarm surge protection devices (in data systems). This standard is also used in Russia, therefore results of our tests are also applicable to your country.

— Requirements for the voltage limitation include the maximum continuous operational voltage, insulation resistance (leakage current) at such maximum voltage, safety voltage level, i.e. the limitation voltage, resistance to pulse current impact, damage type in case of overload, voltage type resulted from overvoltage and dead space. Dead space refers to the location where the element is not sensitive yet. After actuation we shall identify in which locations the dead space is presented, and if it will affect the safety of the protected system or not. Next is the current limitation requirement, that is to say, a nominal current, resistance sequence, that is allowed to be connected to the line without changing its parameters, time-current actuation parameter, resetting time, the maximum cutoff voltage, operational test, resistance to alternating current and resistance to current pulses. This concerns SPD that include current limiting elements. As you can see, there are many parameters.

— We generally need the following parameters that are tested in our laboratory. Actually, we purchased the instrumentation by taking into account the railway systems, however, their pulse parameters excess the others, so it is suitable for other systems as well. If we look at the tested pulse parameters, these provide stability as per category C1 at the pulse of 500 А 8/20 µs, and С2 at 5 kA 8/20 µs. In case of the category B1 telecommunication pulse, we are able to test up to 10 kV, which is very high. Measurement of the safety voltage level Up. Measurement of the resetting time and dead space. The instrumentation allows memorizing oscillograms and transmit them to a PC, therefore, generally the test documentation is stored in electronic form, in which case everyone who desire to check the fact of test, is free to do it. In practice, these documents are always verified, including by specialized institution of that country.

— Climatic tests appeared to be very serious. Since we are going to sale the devices to various countries of the world, we are now negotiating with African ones, such tests have major significance. I can say, that not all hardware enclosures withstand special temperatures. There are many climatic zones in Russia, I suppose, you're very concerned of this issue. Well, what do we test? Again, we refer to the same standards, where additional requirements are contained as to other standards, here you can see them. High temperature (80˚ С) and 93 %, moisture resistance tests for 10 days. Cyclic ambient tests at pulse overvoltage, it is the cycle B, that is to say, mixed cycle, temperature and overvoltage together. Look, these take about 6 days, maybe 5 days. And additional tests: dry warm, at the heat degrees of 80˚ С, humidity percent and cool. I mean, our instrumentation shall test within the range of 40 to +180˚С at the humidity of 20 to 90 %. Capacitance is high, which is relevant for us, because the rooms can be large.

— There are more of other parameters, which are relevant for the designer, in order to be sure, that all these data, which are given in the catalogue, or the data of elements have been proven. The maximum continuous operational voltage, insulation resistance, leakage current, nominal current allowed to be conducted through our protective hardware without damage shall always be tested. Resistance sequence and limit frequency. All these technical data are to be added to our catalogues.

— These are in Polish, so I am to translate for you. I'll try to make it clear for you. For example, look at the parameters given by the CCTV manufacturer - these for the video surge protector. Which parameters arise, that we have not even mentioned earlier at all. For example, the level of protection at 1 kV per microsecond. Nothing is clear, who introduced this parameter, for what purpose? Maybe, it was translated from Chinese to Polish at that moment. Protection voltage over 2.4 V or higher, which can be 1,000 V and so on. Sorry, there is a lack of accuracy. A sort of tricks. Just read, they specified earthing, however, it is not clear, what is "mass" and "re-earthing bolt, indirectly". I'm sure, they are great sellers, but do not know actually what they sell. Look, there is a statement of testing according to the category standard, which category is C2. No any more details of tested samples and methods.