Jun. 01, 2010

Light Work

Photovoltaic Solar Plant Applies Thermal Imaging Cameras to Protect the Perimeter

  • Abertura Photovoltaic Solar Plant spans a surface of over 200 hectares. More than 132,000 solar panels on 2,112 solar trackers with a total installed power of 23.1 Mega Watt peak.Abertura Photovoltaic Solar Plant spans a surface of over 200 hectares. More than 132,000 solar panels on 2,112 solar trackers with a total installed power of 23.1 Mega Watt peak.
  • Abertura Photovoltaic Solar Plant spans a surface of over 200 hectares. More than 132,000 solar panels on 2,112 solar trackers with a total installed power of 23.1 Mega Watt peak.
  • Schematic overview of the thermal fence installed at Abertura.
  • Mr. E. Ces, Commercial Director of Soviter, a FLIR Systems distributor in Spain – Miss E. Muñoz, Technical Maintenance of Iberdrola Ingeniería Y Construcción. – Miss M. Valien, Technical Department, Vector Cuatro – Mr. A. Vilallonga, Vice-President, Flir

Over the last few years, environmental awareness has increased drastically. Instead of relying only on fossil or nuclear energy for generating electricity, renewable energies have come into play. Power is generated from natural resources such as wind, water, tides, geothermal heat and solar energy. One of the main solar plants in Spain is the Abertura Solar Park. It represents an investment of over 225 Million Euro and FLIR Systems have provided a total surveillance solution consisting of thermal imaging cameras, network video storage and video analytics.

With the help of photovoltaic cells, commonly called solar panels, light can be converted to electricity. Although Germany and Japan have long led the field in solar thermal energy production, today Spain is the hub for solar energy activity. Abertura Photovoltaic Solar Plant, the largest installation in the world with dual-axis solar trackers, is one of the main sites in Spain and located in the Spanish province of Cáceres. The location is considered ideal because it gets almost 2,000 net hours of sun per year and the land is very flat, which makes it ideal for the installation of photovoltaic solar panels.

The solar trackers of the 23.1 Megawatt (MWp) Abertura Solar project make the panels move both north, south, east and west. They assure that the solar panels are always ideally positioned towards the sun, which drastically increases the plant's capacity. Abertura Solar consists of more than two hundred 115 kilowatt (kWp) blocks and was completed in July 2008. The entire installation covers an area of more than 2,000,000 m2.

Generation and Distribution
Vector Cuatro is an active company in Spain for strategic and financial consulting on investments in solar photovoltaic power plants. Currently, Vector Cuatro manages and/or administers nearly 90 MW. It is the only management and administration company that has participated in the complete process of promotion, development, structuring, financing and start up of photovoltaic installations for third parties. Today, Vector Cuatro manages 13 solar power plants in Spain, for nine of which the management started after the plants had been constructed.

The solar plant in Abertura, was developed and constructed entirely under the supervision of Vector Cuatro.

Just as in many other similar installations, the energy generated by the photovoltaic cells is first inverted from DC to AC. Each of the over two thousand trackers generates 11.5 kWp at 400 VDC. Once the 400 VDC has been inverted to AC, a step-up transformer increases the voltage to 20 kV in order to transport the electrical energy. Finally, this energy is uploaded to the distribution grid of the local utility at 45 kV.
At Abertura, the utility that is uploading the electricity to its grid and distributing it is Grupo Iberdrola. Following a period of strong international expansion, Iberdrola has established itself as one of the four largest energy companies in the world by market capitalization. The group has made a major commitment to the use of cleaner technologies, becoming a world leader in solar and wind energy and is now one of the companies with the lowest CO2 emission levels in the electricity sector. The company's Substations department also designed and built the transformer substation at Abertura.

An investment of 225 Million Euro Needs to Be Protected
"The development and construction of the Abertura solar power plant has been a giant project", explains Borja Escalada, Managing Partner of the Vector Cuatro Group. "We were involved in every step; acquiring the land on which the plant is installed; purchasing and installing the photovoltaic cells and solar trackers and all the other aspects. The entire solar plant represents a total investment of approx. 225 million Euro. Depending on the climatic conditions, we generate electricity for about 25 million each year."

"It is clear that an investment of 225 million Euro needs to be protected. There are several threats for an installation of this size. First of all, photovoltaic panels and our huge network of copper cables are expensive and therefore theft is a big concern. But the site not only needs to be protected against theft: we need to protect potential thieves and other intruders against themselves as well because the site contains high voltage installations and people gaining unauthorized access might seriously hurt themselves or, even worse, be killed", continues Escalada.
"Also for Iberdrola it is important that the plant is well protected", says Esther Muñoz, Technical Maintenance of Iberdrola Ingeniería Y Construcción. "Power generating facilities are vital for a country's economy and are a potential target for terrorism. If anything should happen to the plant due to sabotage or terrorism we would lose a part of our grid, so that we would not be able to serve our customers. This needs to be avoided at all times."

Long Perimeter
"Securing a perimeter of almost 9 km is however not an easy task", says Escalada. "During the daytime we are not too worried since we have a maintenance crew of 4 or 5 people that are constantly walking around on the site. Security at night, however, is a different issue."
"Although we have experience with this in the other solar plants we are managing, Abertura was the first plant at which we could decide for ourselves what the best security option would be. The other plants started to be managed by Vector Cuatro after the security system had already been decided and contracted."

"We looked at several possibilities. Conventional CCTV with lighting or infrared illuminators, walking patrols, passive IR barriers and thermal imaging cameras. After careful evaluation of each option, we have chosen thermal imaging cameras for multiple reasons. The entire perimeter around the plant cannot be lit up; this would be far too intrusive for the area in which the solar plant is located. Installing and maintaining light is also an expensive exercise and uses a lot of power."

No Options
"Infrared illuminators are also expensive. Furthermore, infrared illumination does not offer the same range performance as thermal imaging cameras at all. This means that more cameras would need to be installed and more civil works be carried out." "Although we have a fence around the entire perimeter, this is not the best solution either. The fence is relatively weak since we need to have large holes in it so that animals can get through. But even if the fence were stronger, we would still need to install detectors. In order to see if an alarm is false or not, a CCTV system with lights and infrared illuminators would need to be installed anyway."

"Finally we looked at patrolling the area. But apart from the fact that guards are a costly exercise, we recognized another, more unexpected problem. Abertura is a sandy location where a lot of dust can be produced. Patrolling the entire area means that the guards would need to drive around in a car during the night as well, which would produce a lot of dust. This might not seem to be important, but it is: in order to keep the solar panels as effective as possible, we need to remove the dust from them. We currently do this twice a year and each cleaning exercise costs about 100,000 Euro. We estimated that if we had the area patrolled during the night, we would need one extra cleaning per year."

Considering Total Cost of Ownership
"I got in contact with Esteban Ces of Soviter, a FLIR Systems distributor in Spain. He explained to me the concept of the thermal fence and the advantages of using a video analytics solution based on thermal imaging cameras. After a thorough calculation of installation cost, and even more importantly, of the Total Cost of Ownership, we decided to go for this option."

"To protect the 9 kilometer perimeter we have installed 27 FLIR Systems thermal imaging cameras: two VSR-6, six SR-19, five SR-35 and twelve SR-50 create a thermal fence around the solar plant. Two SR-100 thermal imaging cameras, mounted on a pan/tilt were installed separately in addition to this thermal fence. Vector Cuatro also ordered two spare units that can be installed if something should go wrong with one of the thermal cameras. So far, there has been no need to use them", explains Esteban Ces of Soviter.

"We have chosen not only the thermal imaging cameras, but a lot of the other material we needed comes from the same source as well. FLIR Networked Systems, a separate division, provided us with mini servers, input/output boxes, video processing units and network digital video recorders. The software used to manage the entire systems is FLIR Sensors Manager. This out-of-the-box software allows for the easy installation and management of the thermal imaging cameras and other sensors in a TCP/IP network."

The Thermal Fence
"The principle of the thermal fence is quite simple: all cameras are installed along the perimeter. Using the Sensors Manager software we define "trip wires", a video analytics algorithm, to detect if someone is trying to bridge the perimeter. If someone crosses a line which we have set in the video analytics software, a light will start to flash and an acoustic alarm will go off as well. The operator will immediately see the image on his screen of the camera that has created the alarm. He can then determine if it is a false alarm created, for example, by an animal or not. If it is a real alarm and the intruder is not scared away by the light and sound, the operator will call the police who can be on the scene within minutes."
"25 observation posts are installed along the perimeter. An observation post consists of a fixed thermal imaging camera that covers a certain part of the perimeter, a light/sound beacon and in some cases a CCTV camera that can also be used during daylight."
"An electrical cabinet is installed at each observation post. The video and data of the thermal imaging camera and the CCTV camera are transferred to a mini server. The beacon is also connected via a FLIR input/output box. All signals are converted to TCP/IP by the mini server, and an Ethernet to fiber optics converter ensures that all signals are transferred over the long distance to the control room. Here, the data is put on a TCP/IP network again with a fiber optics to Ethernet converter."

Days and Nights
"A computer running FLIR Sensors Manager is connected on the same Local Area Network (LAN) and displays the images of the thermal cameras. It also enables the setting the required alarm rules which are then sent to the video processing units. They are constantly analyzing the thermal images arriving from the cameras and, if they detect an anomaly, they send a signal to the observation post that is generating the alarm. The Mini Server sends a signal to the I/O box where a contact closes and a sound/light alarm will goes off. At the same time the operator will get the image of the camera that provoked the alarm on his screen so that he can take the necessary action."
"Finally, in the control room, the nDVRs are connected to the LAN. They continuously record all images from all of the thermal imaging cameras. They have the capacity to store all the images for a period of 15 days, and afterwards they overwrite the old data."
"The combination of the thermal imaging cameras and the video analytics is perfect. During the night there is great thermal contrast between the environment and a potential intruder, which means that we only need two or three pixels to detect something. This means that we can detect potential intruders at an extremely long distance. In fact, thermal imaging cameras provide much more information to video analytics than CCTV cameras."

Thermal Imaging, the Preferred ­Solution

"We are extremely happy with the thermal fence", says Escalada. "Not only is it a cost effective solution due to the fact that we did not need to do a huge amount of civil works and that we are not consuming a lot of electricity, it is also very effective as well. If I compare this security installation with the ones we have at other solar plants we are managing, I can only say it beats them all. We have practically no false alarms and are able to protect the entire perimeter with just one operator."
"We will definitely choose the same solution for future solar plants that will be constructed, and when the security system in existing solar plants needs to be replaced, it will be with a thermal solution as well", concludes Escalada.


Flir Commercial Vision Systems B.V.
Charles Petitweg 21
4847 NW Teteringen – Breda
The Netherlands
Phone: 0031 (0) 765 79 41 94
Telefax: 0031 (0) 765 79 41 99

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