Webinar «Surge protection of low-current lines, part 1», page 4

The 4th webinar about Surge Protection

Webinar text. Page 4

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Protection of a video camera

Protection of a video camera

Примеры защиты от перенапряжений Examples of surge protection
Защита камерного пункта Protection of a video camera

 

— Here we see an example of cable point protection. We have already shown it, I just want to remind you that this is a signal protection with a coaxial cable. Here are the BNC terminals and protection with power supply, since we installed this protection in zone 0B, we do not expect a partial lightning current to flow through our elements.

 

 

Protection circuit of the CCTV surveillance center

Protection circuit of the CCTV surveillance center

Защита системы видеонаблюдения CCTV CCTV security protection 
Схема защиты центра видеонаблюдения со стороны наружных кабелей питания, видеосигналов и сигнала управления Protection scheme of the video surveillance center from the side of external power cables, video signals and control signal

 

— Protective shield is at the cable exit from the object, here we see the power supply network protection. Here is a large section of cores. We expect partial lightning currents, and such elements, arresters are installed here to divert this energy. Considering signal lines, the control of the camera in one shield here, and if we look here, these are the video signal elements. We specifically installed an additional copper or brass plate to reduce the inductance between these elements. This is our PE bus that is grounded by a short conductor.

 

Surge protection of multiplexer

Surge protection of multiplexer

Защита мультиплексера от перенапряжений Surge protection of multiplexer

 

— In large objects, for example, at the customs point where there is a large number of cameras, we have to build large boards. Now the signal has changed to the signal standard, these are IP cameras, not BNC, a little different systems, but still there are some. Here we see the camera control protection, power protection.

SPDs for the protection of the CCTV

SPDs for the protection of the CCTV

Комплексные УЗИП для защиты 2-х камерной установки с индикацией неисправности Integrated SPDs for protecion of two-cameras unit with fault signaling
УЗИП для защиты центра видеонаблюдения SPDs for the protection of the CCTV

 

— Modern "LEUTRON" and "RST" elements. Again, we see an SPD with a fault signaling. Please look at these two protection elements.

 

 

 

Light pole with video camera

Light pole with video camera

Осветительный столб с камерным пунктом Light pole with a video camera
защита от перенапряжений surge protection
столб column
винтовый зажим screw terminal
контрольно-измерительная коробка control-and-measuring box
крестообразный зажим cross terminal
вертикальный заземлитель Galmar vertical grounding switch Galmar

 

— When we install such elements outside, we must remember that low-current systems do not withstand partial lightning currents. We must always install the elements of these systems in a zone protected from direct lightning strike. In this case there is this column that will take the lightning strike first. Then the camera will respond only to induced currents or grounding potentials. Here we install one protection circuit on two cables, as you saw in the previous figure. There always must be local grounding. We cannot allow surge current to flow through the yellow-green core for kilometers, because the surge on this inductance can be enormous.

 

 

Protection circuit of the RST-safe CCTV

Protection circuit of the RST-safe CCTV

Защита Центра Видеонаблюдения CCTV Protection of the CCTV surveillance center
Защитная схема RST- safe CCTV Protection circuit of the RST-safe CCTV
для шкафов 19 for 19 boards
для вешания на стенах for wall mounting
в свободностоящем корпусе for freestanding enclosure

 

— If we are looking for elements, we must match them with the standards that the manufacturer applied. If we have a 19'' cabinet in the system, this standard has taken root in the world, then we must install protection for such cabinets. We offer such protections.

 

Installation manual of the arrester in the shield

Installation manual of the arrester in the shield

 

— We see that every such device has installation manual. We just have to use our knowledge. Let’s suppose that our cabinet with overvoltage protection at the cable entry to the object is located near the outer wall in the basement under the ground. Then it is obvious that the cable to it will come from the top of the cabinet on this side. And the question is: where to install overvoltage protection? If we install it at the bottom of the cabinet, then all the energy form overvoltage will pass along the protected cabinet. Here the elements will limit it and send it back to earth with a ground conductor. And it is expensive to emit unnecessary energy to our cabinet. In this case you should simply install this SPD at the top. Then our energy will come to our protection and return the shortest way, without radiating over a large length of the protected device. If our cabinet is on the first floor and the cable comes to it from the bottom, then install SPD just at the bottom, the opposite to the way it was installed in the basement.

75 Ohm video signal lines

75 Ohm video signal lines

СХЕМА ЗАЩИТЫ ОТ ПЕРЕНАПРЯЖЕНИЙ SURGE PROTECTION CIRCUIT
Защищённая сторона Protected side
Незащищённая сторона Unprotected side
Существующий заземляющий проводник или шина выравнивания потенциалов Existing grounding conductor or potential equalization bus
ЛИНИИ ВИДЕОСИГНАЛА 75 ОМ 75 OHM VIDEO SIGNAL LINES
Количество защищаемых линий  Number of protected lines
Номинальное напряжение Rated voltage
Волновой импеданс Wave impedance
Максимальный ток DC Maximum DC current
Максимальный разрядный ток (8/20) Maximum discharge current (8/20)
Энергия отводимая при isn Diverted energy at isn
Энергия просачивающаяся Leakage energy
Диапазон рабочих частот Operating frequency range
Вносимое затухание Power attenuation
VSWR в диапазоне рабочих частот (max) VSWR in operating frequency range (max)
Вид разъёма Connector type
Температура хранения Storage temperature
Температура работы Operating temperature
Габариты (в x ш x гл.) Dimensions (HxWxD)
Зажим для подключения PE Terminal for connection of PE
Латунный болт M8 Brass bolt M8

 

— When selecting parameters, we always read the manufacturer's data and look close. In this case, for example, a very important parameter is the wave impedance, always in such systems, as a rule, is 75 Ohm. So we can not install an element that is 50 Ohm here, although it often passes the signal anyway. But what is the point, if we can buy a correctly chosen impedance, where there will be no signal attenuation due to the difference in impedance at a certain point.

 

 

 

RST-safe CCTV

RST-safe CCTV

 

— As a result, we get different types of cabinets with video signal protection, control and power supply.

Example of the video camera protection on the roof

Example of the video camera protection on the roof

Защита камерного пункта Protection of a video camera

 

— If for some reason our camera is installed on the roof, for example, this camera monitors the antenna field of one of the radios in Warsaw. So we must protect it from a direct lightning strike and the electrician must design a special lightning protection system.

 

Surge protection of sports facilities

Surge protection of sports facilities

Защита от перенапряжений спортивных объектов
Видеонаблюдение + Оповещание

Protection against overvoltage of sports facilities Video surveillance + Alert

 

— We have already mentioned this, the issue of large objects, large geometric dimensions, for example, sports facilities, where the length of cables will always be large due to their size, and it reaches hundreds of meters, as, for example, in this case.

Football stadium, 2004

Football stadium, 2004

 

— The stadium, where the loudspeakers and camera points that monitor the fans are installed on the crown of this stadium so the fans would not think up something interesting.

 

Loudspeaker outriggers

Loudspeaker outriggers

 

— Outriggers of the loudspeakers are there so that crowd could hear what the speaker is saying. Please, look, an SPD is installed here, and even for this case it is connected with a yellow-green wire. Here the tape goes around the stadium grounded to it. The shortest way is not 0.5 meters, it was not possible here, it is connected to the ground by the shortest way, where we divert the energy of the overvoltage. If we look at these points, see? I can see the speaker points and the camera points on the crown. It is clear that due to the large size, it is very likely for the lightning to strike the stadium. If it does, it is obvious that it will strike the highest points. And the highest points are our loudspeakers and our camera points.

Surge protection shield

Surge protection shield

 

— At such a facility as a stadium, the entry of all cables, you can see that here a huge number of signals returns and enters the central observation point. All cables, all conductors are protected at the entry. Power supply is in another board, here you don’t see it.

 

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