Webinar «Lightning and Lightning Protection at Krzhizhanovsky Power Engineering Institute», page 3

David and Goliaер (gas discharge version)

Streamer flash start

Старт стримерной вспышки – streamer flash start

Почти 100% вероятность возбуждения молнии за 5 с – almost 100% probability of lightning excitation in 5 seconds

1 восходящая молния за 40 грозовых часов – 1 upward lightning in 40 thunder hours

Телебашня в торонто – Television tower in Toronto

Компьютерная модель – computer model

Нет стримерной вспышки – no streamer flash

Нет встречного лидера – no counter leader

Нет удара молнии – no lightning strike

— A corona discharge appears at the stable tower in the electric field of a thunder cloud. This corona discharge emits a cloud of spacial charge into the atmosphere. The spacial charge cloud shields the tower. Lightning simply doesn't see it. And the rocket doesn't manage to make such a charge cloud, and for this reason, the lighting is provoked by the rocket, but not constantly near the tower, which was covered by this charge like by a cap of invisibility. Our corona research in an electric field of a thunder cloud began as a work on the agreement with one American company. And when we began this work, there were such talks. It was the end of the century and there were some notices on the Internet like - Russian specialists have nothing to eat if they took this useless case with the research of a corona discharge in an electric field of a thunder cloud which has and can't have any relation to lighting protection. It was a severe mistake and he had to spend a lot of force to change the public opinion and to make everything believe corona has relation to lightning protection; moreover, this relation is direct.

Встречный лидер вместо аркана – counter leader instead of check cable

Молниезащиту интересуют не правила, но исключения – Lightning protection is interested not in the rules, but in the exceptions

Гипотеза Голда – Gold’s hypothesis

Точка удара молнии определяется местом старта встречного лидера, который притягивает нисходящий лидер – Lightning strike point is determined by the counter leader start place which drags the downstream leader.

— Not a simple object intercepts lightning, but a lightning rod or building standing near. The one counter leader channel interecepts lightning which is formed at the top of the object in the cloud direction in a thunder field and the lightning itself and this thunder cloud. And how the discharge develops defines what corona did here. How did it strengthen the electric field and what did this all bring to? It is a large series of researches, which was held not only by ENIN specialists, but by the team consisting of specialists and academic institutes, and Physical Technical Institute of Moscow. It brought to the fact, that our idea how to influence lightning changed significantly and there are no ideas which we did not have before.

See slide 27. That very experiment was the start point for us. Flying rocket and stationary building. Corona effect is very powerful.

Тросовые молниеотводы для защиты ОРУ ПС – catenary wire lightning rods for the protection of outdoor switch gear of a substation 

Технические преимущества - Technical advantages

Более высокая надежность защиты по сравнению со стержневыми той же высоты - higher protection reliability in comparison to rod lightning rods of the same height.

Устранение повреждений цепей вторичной коммутации при грозовых воздействиях- elimination of damages of secondary control wiring circuit at thunder impacts

Защита от несанкционированного ввода тока молнии в подземные коммуникации, в том числе воздуховоды включателей- protection from unsanctioned entry of lightning current into underground utilities, in particular air ducts of switches

Уровень проработанности вопроса - The level of working on the issue

Создана методика расчет сложных систем тросовых молниеотводов для защиты ПС- the method for calculation of complex systems of catenary wire lightning rods for protecting substations was created

Проведены макетные испытания тросовых молниеотводов в промежутках длиной до 30 м - layout tests of catenary wire lightning rods in the gaps up to 30 m long were held

— If to put wire system insread of it and allow this wire system to organize a solid cloud of spacial charge, then the reliability of the whole substation won't be less than three 9s. One lightning out of a thousand maybe will get there.

Активные молниеотводы- миф, а не реальность- ESE lightning rods, myth but not a reality 

При малой длительности управляющего напряжения (2-3 мкс) формируется мощная стримерная вспышка. Своим объемным зарядом она снижает электрическое поле у вершины молниеотвода и тем самым прерывает развитие встречного лидера - With a short duration of the managing voltage (2-3 ms) a powerful streamer flash is being formed. With its special charge it reduces the electric field at the top of the lightning rod and stops the development of this counter leader.

— It brought to the fact, that with the help of corona discharge research, the speculation of the so-called ESE lightning rods became clear. ESE lightnign rods could function if high voltage pulses which they form, were able to develop forming counter leaders which would capture lightning at far distances. But the dimensional sizes of these lightning rods are so small, that it is impossible to put the pulse source which would give pulse duration sufficient for the leader development into them. High voltage which forms active lightning rods dures only for units of microseconds. For this time, units of microseconds from the top of the ESE lightning rod, a powerful streamer flash blazes up. It emits a great quantity of spacial charge into the gap. And this spacial charge is covering the ESE lightning rod like a hat and reduces the very strong intensity of the electric field there. In the result, no ionization processes from this ESE lightning rod are formed at all. IN the result, lightning rod doesn't attract a discharge; it functions in a reverse way. It prevents from normal development. The one which would happen if there were no ESE lightning rod but a simple metal thing. And the experiments show that this influence is quite serious. For example, electric strength of aerial insulation increases to 20% at its expence during the laboratory tests. And all the experiments held recently with ESE lightning rods aimed to study their efficiency in field and laboratory conditions brought to the same results. But ESE lightning rods attract the lightning channel worse than an ordinary lightning rod made of simple metal.

Эксперимент в Сарове - Experiment in Sarov 

Ток в грунте – current in the ground 75 kA

— These channels develop to great distances. For exampple, the picture you see now was made at the Institute of Experimental Physics in Sarov, where the channels developed up to 30 meters long at the ligtning current of 75 kA. Why do I mention this? When the ground is weakly conductive, such channels really often develop to quite decent distances. But if it is black soil, you don't have to worry about this process, because in well conductive soils nobody saw such channels. And really nobody saw them, because the voltage sources at which these experiments were held were non-energy consumpting and in well conductive soil they could not support electric field for a long time. It did not work out. And quite recently upon the task of the federal network company a big team consisting of Krzhizhanovsky Enery Institute - our Insitute, United Institute of high temperatures - it is an Academic Institute, from Troitsk Innovation Center - it is Rosatom's Institute, made on work, the result of which was the generator of impulse currents with the voltage of two million volt with the energy of 4 MJ.

Где еще остро нужна наука- Where else science is critically needed

1. Оценка опасности импульсных воздействий напряжения в микросекундном временном диапазоне- Estimation of danger of voltage impulse actions in a microsecond time frame

2.  Расчет надежности защиты мультитросовыми молниеотводами с учетом неоднородностей в слое объемного заряда короны - Calculation of reliability of protection by multi-wire lightning rods with the consideration of inhomogenuities in the layer of the spatial corona charge 

3. Учет полярности молнии при расчете надежности защиты от прямых ударов молнии - Consideration of lightning polarity at the calculation of protection reliability on direct lightning strikes

4. Оценка эффективности работы коронирующих молниезащитных систем с учетом ветрового сноса объемного заряда - Estimation of efficiency of corona lightning protection systems functioning considering the wind deflection of a spatial charge

5. Разработка системы грозовой опасности для современных летательных аппаратов - Development of a system of thunder danger for modern aircrafts

6. Разработка национального нормативного документа по молниезащите нового поколения - Development of national regulatory document on new generation of lightning protection

— Today we can surely say that the main task should be development of a crucially new regulatory document on lightning protection covering interestes of the whole country branch and based on the things we know today. And first of all, we need to talk about the processess in the ground, which we have not been considering for a long time. This work on formation of a new regulatory document on lightning protection is very significant for all the branches of our national economy. Are there any other tasks? Of course, there are. In some moments, they are not less significant. For example, we know that there are negative and positive lightning. It is known that about 10% of lightning on the territory of the Russian Federation are positive. It is known that the parameters of these lightning differ strongly - by the pulse duration, by the current value and by the growth speed of this current. Is it reflected in our regulatory documents somehow?

Of course it is correct but two things will prevent this. The first one - local inhomogenuities in corona development on extended electrodes will prevent. We need to get how to deal with them. Another task. But there is a primitive influence. Corona charge is blown off by the wind. How to make it so that the wind influence would not disturb operation of extended shielding systems? That's another task. These are just the examples of such tasks. There are many of them and for 2,5 centuries of lightning protection research we still have not solved all of them. Not all the tasks are solved. I think there are enough of them for many generations ahead. I'd like to finish my report and wish luck to the new generation of scientific workers who will work on lightning and wish them not to be afraid of unsolved tasks, because unsolved tasks are not solved for only one reason - nobody seriously tried to solve them. So if you begin, you will probably succeed. Good luck to you, dear colleagues!

Thank you for your attention

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