Traditionally, an estate’s primary source of electrical power is the grid. However, this is no longer reliable, so a backup system is essential to maintain continuity of supply. There are various options when looking for a reliable power supply.
The following options are available to estates, depending on what they need to power, and how long they need independently generated power.
UPS (Uninterruptible Power Supply): These systems are typically used for short-duration backups (around 10 minutes) and are designed to protect the power feed to equipment connected to the UPS output. Adding extra batteries makes it possible to extend the backup time, but this increases the cost of the system exponentially.
Inverter/battery/solar: These systems are designed to provide a long-duration backup (hours or days) and provide limited power protection to connected equipment. They may be set up where there is very little or no dependence on the grid, and may rely mainly on the sun to charge the batteries and supply power to the security system. The most common use is for maintaining power supply and reducing electricity costs.
Depending on the size of the system, an inverter/battery/solar system is far more cost-effective and reliable, and carries warranties of up to 10 years on the batteries and inverter.
Uninterrupted power to the perimeter and entrance
Copper cables should be positioned so that they are not easily accessible. This will inhibit accidental damage or theft, and prevent the security system from being disabled. Equipment should always be located in a secure environment.
Maintenance of the systems should be done regularly to prevent equipment breakdowns. This would include visual inspections to check for possible damage or tampering with cables and equipment.
Lightning and surge risks
Lightning, usually seasonal, may cause substantial damage to an estate if it strikes directly or nearby. This is not the only cause of electrical/electronic damage to equipment. The most common reason is switching transients (surges) generated by significant switching actions on the mains feed, the most common being loadshedding or power failures.
To protect against lightning and switching surges, Type 1 and Type 2 protection devices must be installed strategically on the (AC) main incomer and secondary distribution boards. This will also protect solar systems and generators on the AC input/output sides. Solar panels (if fitted correctly) produce DC, and the DC inputs to the inverter must have DC protection fitted at the input.
For electric fencing, protection must also be installed on the fence energiser’s output (DC) side.
It is essential that all other equipment, such as security cameras, is protected using Type 3 protection devices. These devices would be used as individual protection (e.g., one per outdoor camera) and should be positioned as close as possible to the equipment to be protected.
All of the protection devices mentioned above rely on a low-impedance single-earth system. In other words, make sure that there is a practical earth system and that all earths are bonded together and, in turn, bonded back to the main earth.
Of critical importance, never forget: No earth means no protection.
Using voltage regulation devices
It is important to note that lightning and surge protection devices are designed to dissipate only very high-speed surges (fast transients). For any other voltage fluctuations (slow surges and sags), other voltage regulation devices, such as Constant Voltage Transformers or Automatic Voltage Regulators, need to be considered to stabilise poor voltage inputs.
Are these precautions necessary?
Even in the event of the Eskom power supply becoming more reliable, the transmission of power still presents many problems due to very old infrastructure in many areas, i.e., cable failures, transformer failures, and cable theft will continue to present problems in the foreseeable future. These issues, as mentioned, also create power failures, which generate switching transients (surges).
Therefore, it is important to maintain an effective lightning/surge protection system at all locations requiring a reliable security system.
The South African market has many suppliers of alternative power supply systems, lightning and surge protection, and voltage regulation devices. When purchasing products, ensure that the company you are dealing with supplies reputable products and has qualified technical knowledge to back up their products.
Incorrect installation of systems or the use of low-cost equipment may lead to the failure of a complete security system. A chain is only as strong as its weakest link.
Fire risk
As mentioned, the use of quality products installed by qualified personnel goes a long way toward mitigating the risk of fire in areas where solar, battery, or generator equipment may be installed.
• Avoid extreme temperatures. Keep your devices and batteries away from extreme hot and cold temperatures.
• Regularly inspect your devices and batteries for any visual damage.
• Fire extinguishers suitable for the type of fire they need to extinguish should be placed in accessible areas to help extinguish any possible fire.
Drensky Technologies is a well-established company that has been active in the end-to-end supply of alternative power products and solutions for protecting and stabilising power supplies since 2006. Its team includes highly qualified technical staff with extensive experience in the solar and electrical industries.
Find out more at www.drensky.co.za
© Technews Publishing (Pty) Ltd. | All Rights Reserved.
printer friendly version