Quality of power, also, has taken the centre stage in the functioning of commercial buildings which have now come to realise that a slight variation in the voltages can cause domino effects in the critical systems. One of the fundamental modifications of the reactive maintenance method to the active power management, where the voltage delivery does not vary with grid instabilities and load variations, is the automatic voltage regulator of AC systems. Voltage regulation technology has much more to do with how the equipment is preserved than merely how the business, which is increasingly becoming an electrical place to operate, continues to do so.
Today, commercial buildings contain advanced electrical loads that require fine-tuning of voltage. Be it variable frequency drives to power HVAC systems or sensitive IT infrastructure to power business operations, any fluctuation in the voltage can directly translate into equipment degradation, unplanned outages and heavy financial losses. Installation of effective automatic voltage regulation systems has thus gone beyond being a desirable addition to infrastructure to being a necessity.
Understanding Automatic Voltage Regulation Technology
Principles behind successful voltage control have their basis on the response of the automatic voltage stabilizer system to an electrical anomaly. Voltage variations in modern commercial buildings occur due to a variety of sources: utility grid, internal load switching, non-linear load harmonic distortion and transient effects such as lightning or switching activity. Depending on the disturbances, the voltage can vary greatly compared to the nominal values, which poses problems in the operations of any equipment that goes well past the scope of basic equipment failure.
What is automatic voltage regulation in principle? These are achieved by continuously monitoring the received level of voltage, making real-time comparisons to pre-established setpoints, and making corresponding adjustments using one of several correction mechanisms. Modern stabilizer automatic voltage regulator systems (compared to statical voltage regulation techniques) utilize dynamic control algorithms, so that the voltage regulation system can react to voltage variations within milliseconds, and provide continuous protection to loads that are connected to the system.
The technology includes multiple different methods of voltage correction. Tap-changing transformers include adjustment of voltage in steps with mechanical switching of transformer taps to offer excellent robust operation with a fixed switching latency. Electronic voltage regulators rely on semiconductor devices and handle stepless, continuous voltage correction with very short response times but potentially also with harmonic content. Voltage regulators driven by a servo command incorporate both mechanical accuracy and electronic control to provide high accuracy voltage regulation needed in sensitive commercial applications.
Key Components and Operating Principles
In modern automatic voltage regulator system there are several subsystems that are combined to provide the best output. The sensing circuit continuously receives the feedback of the input voltage by the action of fine voltage transformers, and is fed back into the control system. Control unit may also have microprocessor-based logic and receives a voltage input and determines what corrections must be made based on a programmed parameter and response characteristics.
The purpose of the power correction stage is quite different depending on the type of regulator, but all are intended to provide consistent output voltage despite variation at the input. Buck-Boost transformers are bidirectional, voltage correcting, series connected windings that allow either voltage boosting or voltage cutting over a specified range. The correction field is typically between 15 per cent and 20 per cent of nominal voltage, which covers most variations in utility supply that are found in commercial applications.
Protection systems are part of the voltage regulation equipment that protects the equipment itself and loads against unusual operating conditions. Output protection circuits control voltages by continuously measuring them and starting a shut down sequence at voltages above safe operating limits. Higher than normal load currents are responded by an overcurrent protection and could indicate a downstream fault or equipment failure.
Commercial Building Applications and Benefits
Use of automatic voltage regulator in AC systems of commercial buildings is applicable to a wide range of electrical load with various voltage sensitivity profiles. HVAC systems, which gives up the highest electrical power in most commercial facilities, enjoy the stability of the voltage supply. Equipments powered by motors like chillers, air handling units and circulation pumps perform better and last longer when they are used at peak voltage.
Controlled voltage conditions have proven to enhance the performance of lighting systems particularly when an electronic ballast or LED driver is employed. Lighting can have visible flicker caused by variances in voltages, color temperature variations, and lower service life of the luminaire. The use of extensive voltage control guarantees the stabilization of light output and helps to achieve the greatest returns on lighting system investments.
Computers, servers, and telecommunications infrastructure are electronic equipment that is sensitive to the availability of the steady supply of voltage. Although internal voltage regulation is provided in many modern electronic devices, upstream voltage stability minimizes stress on internal voltage regulation systems and increases reliability. Automatic voltage stabilizers that finely adjust the voltage when the load condition changes are also being used in the data centers and server rooms.
Energy Efficiency and Cost Implications
Automatic regulation based on voltage optimization provides quantifiable amounts of energy savings in commercial buildings. The efficiency of most electrical equipment is optimum at nominal voltage, and efficiency decreases when the voltage is not within design specifications. Motors can operate with lower efficiency and consume more energy when running at the inefficient voltages that make up a large part of commercial building electrical loads.
Voltage and energy consumption relationships depend on the type of the load but tend to be predictable. Resistance loads like heating elements require power that is proportional to the voltage squared, that is, when there is overvoltage, the energy consumption is excessive and leads to rapid equipment wear. More complex voltage-power characteristics characterize motor loads but usually show optimum efficiency in small ranges of voltages near nominal values.
Lighting systems have been sensitive to voltage optimization and the vast majority of technologies suggest reduced power consumption and increased life when operated under suitably controlled voltage conditions. Magnetic ballast fluorescent lighting systems are especially vulnerable to changes in voltage, whereas LED systems have the advantage of constant DC supply due to well-regulated AC input voltage.
Advanced Control Strategies and Integration
Increasingly, modern-day commercial buildings have integrated building management systems, which synchronize various functions of the building to ensure an optimum level of performance and efficiency. Automatic voltage regulator systems used in commercial applications as stabilizers are designed with communication facilities to allow them to be connected to these larger building control networks. It is integrated to provide centralized control of the power quality parameters and also to react to building wide electrical events.
Smart grid integration is a new application of sophisticated voltage regulation system. Commercial buildings with advanced built-in automatic voltage regulation systems can be included in demand response programs and vary their electrical properties as per the needs of their utility grid. This feature is especially useful when utility grids include more and more sources of renewable energy that are variable in nature.
In a business environment, volume regulation systems are more accurate with load forecasting and predictive control algorithms. In some receptive sense, modern systems assume the need to regulate voltages and pre-program control systems when they subject their history load analysis to an environmental analysis. It is an active solution that reduces voltage transients when loading and switching loads and provides better overall voltage control.
Maintenance and Reliability Considerations
The operational life of commercial buildings directly depends on the reliability of the automatic voltage regulator systems. Voltage regulation equipment preventive maintenance programs should encompass not only the mechanical aspects of the voltage regulation equipment including tap changers and contactors, but also the electronic aspects of the voltage regulation equipment including control circuits and power semiconductors. Various forms of maintenance that are usually performed on a regular schedule are insulation testing, contact testing, calibration testing, and checking the functionality of the protection system.
In commercial applications where the failure of the voltage regulation may cause serious business interruption, the issue of redundancy is critical due to the mission-critical nature of the application. Simultaneous operation of two or more voltage regulators offers a greater capacity and better reliability, and automatic transfer facilities ensure that the load remains on even when one (or more) of the units is in operation or has failed.
Remote monitoring and diagnostic functions are becoming standard parts of commercial grade voltage regulation equipment. The systems are performing in real time, trends analysis and probable failure in the performance that can respond to the maintenance on its own and remove the impact of the unexpected failure. The facility manager can monitor power quality parameters in addition to other vital building systems through integration with building management systems.
Implementation and Selection Criteria
In order to select the right type of automatic voltage stabilizer system that is to be placed in commercial buildings, certain consideration should be given to analysis of nature of electrical load, the nature of conditions of utility supply and performance requirement. Load analysis must also include both steady-state and transient load conditions, identifying equipment that is sensitive to variations in voltage, and determining the magnitude of the possible effect of changes in voltage on the operations of the building.
Characterization of utility supply includes long-term observations of the quality of the incoming voltage, recording of normal variations and unusual occurrences that may impact building functions. Analysis defines the necessary range of correction and speed of response of voltage regulation equipment that provides sufficient protection under all expected working conditions.
Installation of the commercial voltage regulation system considers electrical integration requirements, space requirements, ventilation requirements and accessibility of maintenance. Adequate system sizing should not only consider future load increases but also should not over-specify systems that will raise start-up expenses and fail to deliver corresponding value.
Future Trends and Technological Evolution
Innovation in automatic voltage regulation technology is still being fueled by the development of electrical systems in commercial buildings. The growing use of renewable energy systems in commercial buildings poses new voltage regulation problems between intermittent generation sources and the conventional utility supply. Advanced voltage regulation systems should be capable of supporting more than just the forward and reverse power flows, and should be stable in the face of highly variable generation conditions.
Another recent development that has an impact on the voltage regulation needs of commercial buildings is energy storage integration. Battery energy storage systems may be capable of offering voltage support, energy management functions, and need co-ordination with standard voltage regulation devices to achieve optimal overall system performance.
The digitalization of building systems opens the potential of even better voltage control by improving monitoring, controlling and optimization algorithms. Applications of AI and machine learning can be applied to analyze building electrical patterns to determine the best voltage regulation concepts and anticipate the need to repair buildings when problems arise.
Conclusion
Automatic voltage regulator is far more important to the AC systems of contemporary commercial structures than the equipment protection, including energy conservation and stability of its operation, as well as the long-term maintenance of the equipment per se. Due to the trend of more advanced commercial buildings being reliant on electrical systems, the need to thoroughly regulate voltages continues to increase.
Installation of the systems of the voltage regulation presupposes certain specific knowledge of the electrical specifics of buildings and correct choice of the equipment and long-term investment in the maintenance of the equipment. The benefits, however, are distributed across multiple areas of operation including reduced energy consumption, improved equipment maintenance and increased power quality to sensitive loads.
IET has a long track record of providing electrical engineering solutions that have ensured that commercial buildings in East Africa have continued to perform optimally over the last seven decades. Our experience in power quality solutions, coupled with our knowledge of the electrical infrastructure issues of the region, gives us a unique capability to design and implement automatic voltage regulation systems to provide long-term value. You may need a new commercial facility, or you may need to upgrade or improve your existing electrical infrastructure, our team of qualified engineers is on hand to design tailor made voltage regulation solutions that suit your particular needs. Call IET today to learn how our experienced knowledge can make your building perform better and be more reliable in its operations.