Features of UPS for industrial facilities
Uninterrupted power supply is important both for a single machine at an industrial enterprise, and for a large production complex as a whole. Modern energy systems are quite complex and reliable, but they do not always cope with this task. What types of UPS are used for industrial facilities? What requirements should they meet? And are there any special operating conditions for such equipment?
Industrial UPS Requirements
Given the purpose, it is possible to highlight the main characteristics that uninterruptible power supplies for industrial facilities should have:
- High power output. It is determined by the power of equipment used in enterprises.
- Maximum reliability. It is laid at the stage of development of the design of sources. In their manufacture, components are used that can repeatedly increase the reliability of devices. This, of course, increases the cost of the UPS, but at the same time increases the service life of both the sources themselves and the equipment that they provide with electricity.
- Sophisticated design that facilitates the diagnosis, maintenance and repair of uninterruptible power supplies. This approach provides easy access to all units of the system and minimizes the time required to disassemble or replace UPS components.
- Possibility of scaling and smooth increase of power. This is necessary when increasing the need for power.
Types of Industrial UPS
For industrial purposes, three main types of uninterruptible power supplies are used:
- Standby (otherwise Off-Line or Standby). Such sources are equipped with automatic switches, which, in the event of a power failure, switch the load on the batteries. These are simple and inexpensive systems, but they are not equipped with network voltage stabilizers (which means that the batteries wear out faster) and require a certain time to switch the power to the batteries (about 4 ms). Such UPSs cope only with short-term power outages and are used to service non-responsible production equipment.
- Line-interactive. Such sources are equipped with transformers to stabilize the output voltage. As a result, the number of switching power supplies to the batteries is reduced and battery life is saved. In this case, the UPS is not designed to filter out interference and control the shape of the voltage. They are optimal for uninterrupted power supply of equipment for which only the value of the input voltage is important.
- Online (On-Line). In such sources, a double voltage conversion occurs. First, from variable to constant (it is supplied to the batteries), and then again into variable, which is used to power industrial equipment. In this case, not only the voltage value is clearly controlled, but also the phase, frequency and amplitude of the alternating current. Instead of double conversion, some manufacturers use bi-directional inverters, which alternately perform the functions of a rectifier or inverter. Online UPSs save energy and are more efficient. Such sources are suitable for protecting powerful and network sensitive equipment.
In addition, industrial UPSs can be divided into two groups depending on the type of power supply:
- The first includes uninterruptible power supplies, which are used to protect against interruptions in the power supply of production processes and working equipment. For this purpose, backup or line-interactive type UPSs can be used.
- The second is UPSs that are used for uninterrupted power supply of IT infrastructure: data storage systems or servers. On-Line type sources are suitable for this.
Industrial UPS Operational Conditions
Enterprises of various industries have their own specifics, which means that different requirements are imposed on uninterruptible power supplies. In fact, each such project is unique and needs to be optimized equipment for its own conditions. Here are just a few examples of production specifics:
- The UPSs used at refineries to ensure the safe operation of distillation columns are used for emergency power supply not only of control systems, but also of actuators. Accordingly, they must have high power.
- At geothermal power plants, a by-product is released: gaseous sulfur dioxide. Upon contact with atmospheric moisture, it forms sulfuric acid vapors. It is able to quickly destroy the materials used to make uninterruptible power supplies.
- On offshore oil production platforms, another hazard is increased humidity, salt, and the possibility of horizontal or vertical movement of the base on which the UPS is installed.
- Metallurgical plants have strong electromagnetic fields that can cause interference and cause the circuit breakers to trip.
The above list can be replenished with dozens of other examples. At the same time, regardless of the specifics of an industrial enterprise, reliable operation is required from uninterruptible power supplies for 15–25 years. We can distinguish two main factors affecting the functioning of the UPS:
- Accommodation Sources are strongly discouraged from being placed near energy consumers. They must be protected from the effects of high temperature, polluted air or mechanical influences. For UPSs, the optimum temperature is 20–25 ° С, but they continue to work properly at temperatures up to 45 ° С. Further increase it reduces the battery life, because all chemical processes in them are accelerated.
Dusty air is also harmful. Fine dust plays the role of an abrasive and leads to wear of the working surfaces of the fans and the failure of their bearings. You can try using a UPS without fans, but it is much more reliable to initially protect them from such influences. For this, the equipment must be placed in a separate room with a maintained temperature regime and clean air. - Electricity recovery. The very idea of returning part of the electricity to the network and its reuse is certainly useful. It allows you to reduce energy consumption. Recovery systems are actively used, for example, in rail transport, but they are harmful to uninterruptible power supplies. When using reverse energy, the voltage on the DC bus increases. As a result, protection trips and the UPS transfers to bypass mode. It is impossible to completely exclude the consequences of recovery. They can only be minimized using transformer uninterruptible power supplies.