The twelfth event from the series "Grounding and lightning protection: questions and problems arising in the design
Webinar text. Page 3
Quick navigation through slides:
1. Lightning and lightning protection at Krzhizhanovsky Power Engineering Institute
2. Statement of M.V.Lomonosov about lightning
3. Message of Franklin to count Shuvalov
4. The theory of J.Townsend
5. Air ionization threshold
6. Professor I.S. Stekolnikov’s work
7. Experiments of V.S. Komelkov
8. Laboratory of world records
9. Voltage pulse with a low angle front
10. What changed in the researches of lightning rods?
11. Dependence of the result on the voltage front pulse
12. Leader mechanism of spark and lightning
13. Why do long spark and lightning need a complex structure?
14. Role of streamer zone and spacial charge casing
15. Elementary theory of a leader
16. Theory extrapolation
17. Russian protection zones – where do they come from?
18. Pictures of researches
19. Lightning way
20. ENIN statistical theory
21. Methodical bases of calculation of a number of lightning strikes into overhead power lines
22. Possibilities of a statistical method
23. Influence of the working voltage
24. Influence of a forest area along the overhead power line route
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25. David and Goliath (gas discharge version)
26. Corona and lightning
27. Streamer flash start
28. Gold’s hypothesis
29. Practical implementation
30. Catenary wire lightning rods for the protection of switchyard substations
31. Expected results
32. ESE lightning rods – myth not a reality
33. Danger of spak channels long the ground surface
34. Experiment in Sarov
35. United field tests by ENIN, OIV RAN, TINITI
36. Where else science is required
David and Goliaер (gas discharge version)
Давид и Голиаф – David and Goliath
Газоразрядная версия – gas discharge version
Старт стримерной вспышки – streamer flash start
Нагрев плазмы в объеме стема до 5000 К – heating of plasma in the stem volume up to 5000 K
Стадии процесса – process stages
- Квазистационарная корона от вершина – Quasi stationary corona from the top
- Переход короны в стримерную форму – Transition of corona to streamer form
- Рождение лидера в стеме короны – Leader origination in corona’s stem
- Развитие жизнеспособного лидера – Development of a sustainable leader
Now I have to tell about another figure, which doesn't have any relation to lightning protection. But this person, our only high-voltage engineer Valery Ivanovich Popkov - academician, former academician, secretary of the department of technical sciences, former president of the International Electrotechnical COmmission, who recieved the medal of the Hero of Socialist Labour for working at this Commission. That is surreal. Imagine, he was the head of the International Commission and was awarded the title of the Hero of Social Labour. What for? Because he managed to orient this commission the way it would be useful for the development of technique in the Soviet Union. So, Valery Ivanovich Popkov was one of the most educated people who I ever met at the Institute. He was very well technically prepared. He knew electrodynamics well, electric fields and was only working on one task - corona. Corona discharge is an antipode of lightning, because lightning is the most energetic discharge, corona is the weakest. Though corona lossess were significant at that time. Popkov was interested in the corona from all the positions. And first of all, from the position of electronic-capacity technology, because the charges formed by the corona could be used in a row of technological processes. It is purification of gases, division of particles of different origin, it is painting, coating of surfaces by special compositions. Popkov was very interested in all that and in the result, Popkov separated of our laboratory of high-voltage gas discharge and lightning protection and he organized the laboratory of high voltages. He always told us:
Corona and lightning
Корона и молния – corona and lightning
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
25-30 восходящих молний за 40 грозовых часов – 25-30 upward lightning in 40 thunder hours
— There is such an experiment. The whole world has been playing around with trigger lightning for many years. Trigger lightning is the following thing. They shoot a small rocket, for example, meteorological, about a meter long, which drags a thin grounded wire. And this rocket rises up to 200 meters in a thunder environment and with the probabiity of more than 50 % it provokes a lightning discharge. One thing is astonishing. There is a telemast of the same height nearby, or maybe even higher. It had been standing there for years and was not hit by lightning more often than 2-3 times per year. And the rocket provokes a discharge in five seconds. Why does it happen so? The difference is only in one thing.
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.
Hypothesis of Gold
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.
Practical implementation
Практическая реализация – practical implementation
Незащищенный объект – unprotected object
Многоочаговая система – multifocal system
— The point is as follows. A construction was built over some object, it looked like an umbrella without a coating- only spokes. And on these spokes there were needles 10 cm high, and the number of these needles could be up to several thousand units, even ten thousands. And the matter was as follows, when these needles start to shield, then each needle was acting independently from another one. But gradually, the spacial charge cloud over all of them was united into one system and after this union each needle acted like an element of a common shielding system. All together these needles created larger current that one single needle in a free space. And the current through each needle was so low, that it was not able to heat up the air around this needle and no counter channel which would intercept lightning was formed from this needle. Such a protection system, called DAS was created by Roy Carpenter. Its physical matter was revealed in the researches I am talking about. And the matter of this thing was as follows. It is not a lightning rod. Such an umbrella doesn't have any protection zone, but placed above some construction, for example, antenna system; it is completely eliminated by the strike into the system. And electromagnetic pickups are also eliminated this way. The application of this thing was limited, because what for should it be applied? For antenna, like television antenna. Or like it is shown in this picture, for the chandelier, which lights up the territory; in this case it is an airport. It is a very limited thing. But this system caused a lot of thoughts. Can we make such a shielding system which would close a large space on the ground? For example distribution device of highvoltage substation. If it could be fone, then the number of strikes into such a substation would be reduced sharply. The number of electromagentic pickups would also reduce. And it would be a wonderful system then. ENIN had been working in this direction for several years. And the works in these directions showed the following, what if to refuse from rod lightning protection of a substation. And substations are mainly protected by rods nowadays.
Catenary wire lightning rods for the protection of outdooor switch gear of a substation
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.
Expected results
Ожидаемые результаты – expected results
Тросовая молниезащита ПС - Catenary wire lightning protection of substations:
Обеспечение защиты на территории ОРУ ПС 110-750 кВ от прямых ударов молнии с надежностью свыше 0,999 - provision of protection for a territory of a -switchyard of substations 110-750 kV from direct lightning strikes with a reliability higher than 0,999
Полная ликвидация опасных импульсных воздействий на цепи вторичной коммутации при растекании токов молнии в грунте на территории ПС- full liquidation of dangerous pulse impacts on secondary wiring circuits at the spreading of the lightning currents in the ground on the territory of the substation
Существенное ослабление воздействия электромагнитных наводок на микропроцессорную технику от тока в канале молнии и в грозотросах - sufficient weakening of electromagnetic pickups impact on microprocessor technical equipment from the lightning channel current and in ground wires;
Разработка программного обеспечения для проектирования тросовой молниезащиты ОРУ ПС современного исполнения и средства ее мониторинга в период опытной эксплуатации - development of software for design of catenary wire lightning protection of a switchyard of a substation of modern execution and the means of monitoring it in the period of test use
Создание проекта и опытная эксплуатация тросовой молниезащиты для ПС СВН; разработка РУ по тросовой молниезащите ПС- creation of the project and test use of catenary wire lightning protection for substation’s video surveillance systems; development of distribution devices on catenary wire lightning protection of a substation.
— Electromagentic pickup from close lightning strikes will reduce three times. There simply won't be any pickup from lightning currents because even if the wires intercept lightning, they will drain the current into the side through the supports. And all this will bring to a completely different system of lightning protection of larger square objects. ENIN held such a work. There exist offers on the construction of such a system today. Unfortunately the circumstances in the world and in the country do not allow us to use technical novelties now. But such works exist and I am sure they will be realized finally. I have to say one thing about corona. It is corona research which was held during quite a decent period of time at the Institute and I have to tell, this corona research is my life-time and true love.
ESE lightning rods – myth, but not a reality
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.
Danger of spak channels along the ground surface
Опасность искровых каналов вдоль поверхности грунта – danger of spark channels along the ground surface
Развитие искры в воздухе – development of the spark in the air
Развитие искры в грунте – development of the spark in the ground
— In the result of that, ionization processess happen in the ground, in particular ionization processes in the form of development of long channels, which may move along the ground surface to the distances of dozens of meters. This process is not new in fact. It is quite well known. It was observed in natural conditions 50 years ago. Today, the talks about it began again and they are connected with the fact that modern technical facilities have a very developed underground network of utilities. And these are utilities of processor equipment first of all and damage of these utilities may be more serious than damage of the energy equipment. It is not a rare thing when such events happen.
Experiment in Sarov
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.
United field tests of ENIN, OIVT RAN, TRINITI
Совместные полевые испытания ЭНИН, ОИВТ РАН, ТРИНИТИ («Физика плазмы» № 2,2016 )- United field tests of ENIN, OIVT RAN, TRINITI (“Plasma physics” № 2, 2016)
Металлическая сетка – metal mesh
Заземляющий электрод – ground electrode
Грунт - ground
Ток, кА – current, kA
Напряжение, кВ - voltage, kV
Время, мкс – time, ms
Сопротивление заземления, Ом – Grounding resistance, Ohm
4-кратное снижение сопротивления заземления – 4-fold reduction of grounding resistance
— This installation is absolutely unprecedented by its energy parameters, if you want - a world record. And it is a world record on the wheels, because this installation is mounted in two large machines, which can move to any point of our country and hold researches there. And the first cycle of research has just finished, it was made with the help of this generator. The results which I report now are the results which will be published in the magazine "Plasma physics" № 2, edition of 2016. This magazine is being published now. What did they did? The installation was specially brought to high-ohmic ground. Ground resistance of this soil was in one place 50 Ohm*m, in another 100 Ohm*m. But this is posh. It can't be less, only if you go to the swamp. Current pulses with amplitude of 85 kA were formed on this territory. What is this 85 kA? I can tell. At eleast 90 % of lighting has a weaker current. When with the help of these pulses they checked what is done with the grounding resistance. They discovered that ground resistance of such a system dropped in relation to its stationary value in about 5 times.
Now If I come to the end, I would say one thing. We will have a conference on lightning protection in Saint-Petersburg, organized by the "Streamer" company on the 17,18 and 19 of May, during the white nights. What should be the main task for this conference?
Where else science is critically needed
Где еще остро нужна наука- Where else science is critically needed
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Оценка опасности импульсных воздействий напряжения в микросекундном временном диапазоне- Estimation of danger of voltage impulse actions in a microsecond time frame
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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
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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
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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
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Разработка системы грозовой опасности для современных летательных аппаратов - Development of a system of thunder danger for modern aircrafts
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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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