active power filter
  • Active Harmonic Filter

    Active Harmonic Filter

    Overview of Active Harmoinc Filter Active Harmonic Filter(AHF) is a perfect comprehensive solution to power quality problems such as harmonic wave, reactive power, and 3 phase load unbalance. AHF is connected in parallel in power grid, to detect the harmonic wave in real time, generate the reverse-phase compensation current through the converter, and dynamically filter the harmonic wave. The operation of AHF is unaffected by power grid structure and load type, and it will not produce harmonic oscillation with the system, thus perfectly realizing harmonic wave control of various loads. AHF can also realize dynamic reactive compensation, and control the capacitor switching, to improve the power factor. Meanwhile, Active Harmonic Filter has the function of controlling the 3 phase load current unbalance, thus comprehensively solving various power quality problems with power grid. Principle of Active Harmoinc Filter Key Features of Active Harmonic Filter Multifunctional: Harmonic, reactive power and imbalance compensation High harmonic filtering rate: Up to 98% Excellent reactive compensation: High speed, Precise (-0.99≤PF≤0.99), Step-less, Bi-directional (capacitive and inductance) compensation Excellent imbalance correction: Both negative and zero sequence, mitigates neutral current Wide input voltage & frequency range, adapts to tough electrical environments Low thermal loss (≤3% of rated AHF kVA), efficiency ≥ 97% High stability: Infinite impedance to grid, avoids harmonic resonance problems Flexible application: Modular design, embedded in standard or customized cabinet Easy installation and maintenance: Plug-in installation for AHF module replacement and expansion Wide capacity range: 30A~600A for a single cabinet, up 10 cabinets in parallel Environmental adaptability: -10~50°C temperature, compatible with diesel generator Complete protection: Grid Over/Under voltage, AHF over current, over temperature, and more. All faults are recorded in the event log, which is convenient for failure analysis Typical Application of Active Harmonic Filter Harmonics occur usually as follows, ◆Overheating of transformers and conductors ◆Generator instability ◆Capacitor failure ◆Nuisance tripping of fuses and circuit breakers ◆Damage to or failure of sensitive electronic equipment including drive failure ◆Telephone interference ◆Motors experiencing overheating, audible noise and reduced service life ◆High energy costs ◆Downtime and loss of production due to equipment instability. AHF Modular Datasheet Number of phases (system input) 3-phase 3-wire or 3-phase 4-wire Rated frequency 50/60Hz Rated voltage 400 V ±20% Response time <5ms Harmonic mitigation performance 2nd to 50th harmonic Filter Efficiency >97% Total harmonic current distortion THDi <5% Reactive power compensation Rate >0.98(inductive and capacitive compensation) 3 phase unbalance compensation effect <5% Active Loss of system <3% Inverter topology IGBT Controller DSP+FPGA Current ...
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  • Static VAR Generator SVG

    Static VAR Generator SVG

    Overview of Static Var Generator Static Var Generator (SVG) also known as instantaneous stepless reactive power compensators are the ultimate answer to power quality problems caused by low power factor and reactive power demand for a wide  range of segments and applications. They are a high performance, compact, flexible, modular and cost-effective type of active power filters (APF) that provide an instantaneous and effective  response to power quality problems in low or high voltage electric power systems. They enable longer equipment lifetime, higher process reliability, improved power system capacity and stability, and reduced energy losses, complying with most demanding power quality standards and grid codes. Low power factor increases the active energy losses of installations and affects their stability. It is typically caused by inductive or capacitive loads that demand extra reactive power to perform properly. Other contributors to low power factor are harmonic currents produced by nonlinear loads and the change of load in the electric power system. SVG deliver real-time inductive or capacitive reactive power compensation. Rapid response time provides stable and accurate power factor correction without the drawbacks of conventional solutions like capacitor banks and reactor banks. Principle of SVG Static Var Generator is a power electronics-based device connected in parallel with the load that requires harmonics mitigation. SVG works as a controlled current source providing any kind of current waveform in real time. When the load generates inductive or capacitive current, it makes load current lagging or leading the voltage. An SVG detects the pase angle difference and injects in real time leading or lagging current into the electric power systems, making the phase angle of the current almost the same as that of the voltage, bringing fundamental power factor to unity. Key features of SVG ◆PRECISE COMPENSATION Continuously outputs and compensates reactive power to maintain power factor >0.99. The compensation performance is 1.2 times better than a traditional compensation device (capacitor). ◆CAPABLE OF INDUCTIVE AND CAPACITE COMPENSATION Realize inductive and capacitive compensation, avoid under and over compensation issues. ◆SUPPRESS HARMONICS Configures the required amount of reactive current in real-time and compensates the reactive power to filter high order harmonics. ◆FAST RESPONSE Fast configuration capability provides fast analysis and response time. Provides cycle response <5ms and dynamic response <200us. ◆LOW VOLTAGE BENEFITS Output current is not affected by the mains voltage fluctuation, providing stable support for mains voltage. ◆MINIMAL LOSS, BETTER ENERGYEFFICIENCY Adopts new standard IGBT with low power consumption rate and improves full set device efficiency up to 97%. The system provides low power consumption. ◆MODULAR DESIGN, EASY EXTENSION No need for additional re...
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  • Capacitor banks

    Capacitor banks

    What is Capacitor banks? Capacitor banks, a group of several capacitors of the same rating that are connected in series or parallel with each others, help to improve the quality of the electrical power and gives us the more efficient operation of the power system. Capacitor banks are inexpensive if we compare the benefits they deliver to overall power system and can be easily installed anywhere on the network. Automatic Power-factor Correction (APFC) Capacitor Banks also known as Shunt Capacitor Banks (SCB) are installed to provide reactive compensation and power factor correction. The use of APFC improve voltage regulation, saves power loss and improve transmission capabilities. What Does a Capacitor Bank Work? Capacitor banks, work on the same theory that a single capacitor does; they are designed to store electrical energy, just at a greater capacity than a single device. An individual capacitor consists of two conductors which are separated by a dielectric or insulating material. When current is sent through the conductors, an electric field that is static in nature then develops in the dielectric which acts as stored energy. The dielectric is designed to permit a predetermined amount of leakage which will gradually dissipate the energy stored in the device which is one of the larger differences between capacitors and batteries. Typical Applications Our modern world of electronics requires a lot of energy. To meet this demand, energy must be stored electrically for easy access. Capacitors are ideal for storing large electrical energy charges as well as conditioning the flow of energy as needed. Here are some of the typical uses for capacitor banks: • Shunt Capacitor: A shunt is a mechanism that allows electric current to pass around another point in the circuit by creating a low-resistance path. In electrical noise bypass applications, capacitors are used to redirect high-frequency noise to ground before it can propagate throughout the system, but especially to the load. Shunt capacitor banks are used to improve the quality of the electrical supply and thus improve the efficiency of the power systems. • Power-Factor Correction: In transformers and electric motors, capacitor banks are used to correct power-factor lag or phase shift in AC Power Supplies.The power factor of an AC power system is a comparison of the power used by the load, called the “real power,” divided by the power supplied to the load, known as “apparent power.” In other words, the power factor is the ratio of the useful work performed by a circuit compared to the maximum useful work that could have been performed at the supplied voltage and amperage. In electric power distribution, capacitor banks are used for power-factor correction. These banks are needed to counteract inductive loading from devices like electric motors and transmission lines, thus making the load appear to be mostly resistive. In essence, power-factor correction capacitors increase the current-carryi...
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  • MV/HV Statcom

    MV/HV Statcom

    High Voltage SVG/STATCOM High voltage SVG/STATCOM series static var generator using IGBT as the core power modules which can quicklyand continuously provide capacitive or inductive reactive power, achieve constant reactive power, constant voltage and constant power factor control through the assessment point, and ensure the power grid is running stable, high efficiency and high quality. In the power distribution network, the small capacity STATCOM can significantly improve the power quality (improve the power factor, overcome phase imbalance, eliminate voltage flicker and fluctuation, restraining harmonic), if it is installed in some special loads (such as electric arc furnace). Main Function ZDDQ STATCOM has superior advantages compare with conventional fixed capacitor compensator, MCR and TCR. ■ Fast reactive power adjustment ZDDQ STATCOM provides continuous dynamic compensation to power factor along the load variation. It completely eradicates capacitive reactive power delivery to networks and maintain power factor in designed value for network. Statcom has advantages: 1.Fast response, able to implement dynamic compensation(both inductive and capacitive vars) in real time. 2.Effectively avoid parallel resonance. 3.Able to produce and absorb reactive power. 4.Deliver less harmonic to system. ■Restrain voltage fluctuation and flicker Power grid voltage has fluctuation and flicker when high power impact load is operating. Voltage fluctuation and flicker bring negative influence to other nearby customers’ electricity usage and sensitive load by decreasing safety for electricity usage and decreasing efficiency for production, increasing risk of faulty production. STATCOM response time is less than 1ms and it provides smooth dynamic compensation for reactive power. It is more efficient to restrain voltage flicker and reduce voltage fluctuation, improve voltage to meet standard. ■ Constant current, effectively restrain voltage drop ZDDQ STATCOM has characteristic of constant current. It has advantage in voltage control due to its reactive current output is not affected by busbar voltage. System needs more dynamic reactive power when system voltage gets lower. STATCOM reactive current output is not related to system voltage, but the conventional capacitor VAR compensator’s reactive power output is proportional to square value of voltage. STATCOM can provide better support for improving low voltage ride through (LVRT) characteristic in wind power. ■Compensate negative sequence, implement balanced power supply ZDDQ STATCOM has unique chained structure to allow split-phase adjustment and realizes energy interchange between different phases. It provides balanced compensation to load negative sequence by applying Steinmetz balanced principle. STATCOM makes current flow into system with balanced power and desired reactive power. ■Resistance to harmonics, able to compensate the part of harmonic current Due to widely applications of nonlinear load, harmonics ...
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  • Static Var Compensator

    Static Var Compensator

    Static Var Compensation (SVC) Static Var Compensators (SVC) are devices that can quickly and reliably control line voltages. An SVC will typically regulate and control the voltage to the required set point under normal steady state and contingency conditions and thereby provide dynamic, fast response reactive power following system contingencies (e.g. network short circuits, line and generator disconnections). In addition, an SVC can also increase transfer capability, reduce losses, mitigate active power oscillations and prevent over voltages at loss of load. The SVC is customized to fit each customer with their specific needs. The SVC consists of a number of fixed or switched branches, of which at least one branch includes thyristors, and the combination of branches can be varied a lot depending on requirements. An SVC typically includes a combination of at least two of the given items below (e.g. TCR/FC or TCR/TSC/FC): ◆ Thyristor controlled reactor (TCR) ◆ Thyristor switched capacitor (TSC) ◆ Harmonic filter (FC) ◆ Mechanically switched capacitor bank (MSC) or reactor bank (MSR) MV SVC contactor switched APFC capacitor banks MV SVC Contactor switched SVC capacitor banks Most common topologies for SVCs are: TCR/FC or TCR/TSC/FC. The main advantage for using a topology with TSC branch(es) is to reduce the losses (by reducing the filter size). Mechanically switched banks can be included both on HV and LV side of SVC transformer to increase the total reactive power support outside the dynamic range.  SVC control system can be utilized for controlling new or existing external shunt banks. ZDDQ L.V SVC Contactor switched capacitor banks ZDDQ L.V SVC TSC capacitor banks Applications ◆ SVC Solutions for Utilities ◆ SVC Solutions for Metal Industries ◆ SVC Solutions for Mining Industries ◆ SVC Solutions for Chemical Industries ◆ SVC Solutions for Oil and Gas Industries ◆ SVC Solutions for Heavy Industries ◆ SVC Solutions for Automotive Industries
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  • TSC


    Thyristor Switched Capacitors(TSC) TSC is a well established technology that is primarily used to reduce transfer reactances, most notably in bulk transmission corridors. The result is a significant increase in the transient and voltage stability in transmission systems. Thyristor Switched Capacitors enables rapid dynamic modulation of the inserted reactance. At interconnection points between transmission grids, this modulation will provide strong damping torque on inter-area electromechanical oscillations. As a consequence, a TSC rated at around 100 Mvar makes it possible to interconnect grids having generating capacity in the many thousands of megawatts. Often the TSC is combined with fixed series compensation to increase transient stability in the most cost effective way. The TSC concept also enables inherent immunity against subsynchronous resonance (SSR), and thus allows for extended use of series capacitors in specific transmission grids comprising thermal generation. The immunity to SSR is a result of the ABB patented SVR control strategy. TSC Principle There are two main principles supporting TSC technology. First, the TSC provides electromechanical damping between large electrical systems by modulating the reactance of one or more specific interconnecting power lines. In other words, the TSC will provide a variable capacitive reactance. Second, the Thyristor Switched Capacitors/TSC will change its apparent impedance (as seen by the line current) for subsynchronous frequencies in such a way that a potential subsynchronous resonance is avoided. The TSC achieves both objectives by using control algorithms that work concurrently. The controls will function on the thyristor circuit (this in parallel to the main capacitor bank) such that controlled charges are added to the main capacitor, making it a variable capacitor at fundamental frequency but a "virtual inductor" at subsynchronous frequencies. TSC technology From a principal technology point of view, the TSC resembles the conventional series capacitor. The power equipment is located on an isolated steel platform, including the thyristor valve used to control the inductor in parallel with the capacitor bank. The inductor is placed on support insulators outside the platform. Control and protection systems are located on ground potential, together with other auxiliary systems. ZDDQ TSC Products TSC Capacitor banks
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  • Power Factor Correction

    Power Factor Correction

    What is Power Factor? Power that is used by electrical equipment is known as real power. A site may also draw power that is not directly used, this is known as reactive power. The combination of the two is known as apparent power. Power Factor is the relationship between real and apparent power. If a site has poor Power Factor, it could be paying for energy that cannot be used. What is Powre Factor correction? Power Factor Correction (PFC) equipment is a technology which when installed allows the consumer to reduce their electricity bill by maintaining the level of reactive power consumption. If a sites Power Factor falls below a predetermined figure then the electricity company adds reactive power charges to your bill. In general, the strain on electrical infrastructure is reduced if Power Factor is good. Power factor correction PFC systems introduce a reactive load which supplies reactive power of an opposite sign to that exported by a site, thereby having a cancelling effect. The ideal Power Factor ratio is 1:0. Poor Power Factor has a negative impact on a site including drawing more power from the network causing losses at transformers, reducing effective capacity and incurring ‘poor Power Factor’ or ‘reactive power’ charges from the supplier. Advantages of improved power factor include reducing power demand from the network (which will result in lower electricity bills), prolonging lifespan of equipment, reducing losses in supply transformers and increasing the effective capacity of your electrical network. What we offer? 0.4kV Automatic power factor correction 3.3kV Automatic power factor correction:contactors 10kV Automatic power factor correction:contactors
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  • Hybrid Power Factor Correction

    Hybrid Power Factor Correction

    Hybrid power factor correction Hybrid Power Factor Correction provide an instantaneous and effective response to power quality problems in low or high voltage electric power systems with lower cost. They enable longer equipment lifetime, higher process reliability, improved power system capacity and stability, and reduced energy losses, complying with most demanding power quality standards and grid codes. SVG TSC hybrid power factor correction SVG TSC mixed reactive power compensation Active power factor correction systems utilise power electronics and digital control to achieve active reactive current compensation for specific and high performance solutions. The  active power factor correction unit utilises closed loop control to correct power factor with a ¼ cycle (5mS) response.  This is suitable for unsteady fast changing loads such as cranes, welders, saws and debarking machines. However, sites containing loads such as these generally have a steadier base load. Considering active power factor correction produces a significant amount of heat, the question is whether the whole site needs active power factor correction when only part of the site needs it.A hybrid power factor correction system is comprised from both capacitor based and active power factor correction. Active power factor correction is used to cope with the unsteady fast changing portion of total load while capacitor banks support correction by correcting the steadier base load. This system offers the high level performance of an active system combined with the cost effectiveness offered by capacitor bank correction. Typical Design ◆SVG+SVC(Thyristor) ◆Hybrid Active Power Factor Correction with filters Features Hybrid power factor correction is completely step-less, instantaneous, and precise. Moreover, it can help clients realize significant fuel savings on DG operation. Furthermore, ZDDQ's unique priority setting feature allows you to get the maximum out of the installed filter capacity by using any spare capacity for harmonic compensation, load balancing, and neutral compensation Synchronous Rotating Frame Principal for best performance Ultra fast compensation Proven performance on welding Selective Harmonic compensation Step-less Reactive Power Compensation Negative Sequence Compensation (load balancing) Zero Sequence Compensation (neutral compensation) Benefits Performance of Active with cost effectiveness of passive Compliance with prescribed harmonic limits - No penalty Unity Power Factor - higher savings Reduced energy (kVAh) charges - higher savings Reduced peak demand charges - higher savings Reduced fuel consumption in generators - higher savings Ultra fast compensation - effective with fast fluctuating load Proven performance on welding Optimum capacity utilization of electrical infrastructure Optimum capacity utilization of backup generators Improved voltage profile Reduced risk of transformer failure - higher uptime Reduced risk of equipment failure - high...
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  • Advanced Static Var Generator

    Advanced Static Var Generator

    MEC/Multifunction Electricity Controller & Optimizer Multifunction Electricity Controller system has a stronger ability in restraining the voltage fluctuation and flickering, effectively compensates the voltage drops with the drop depth and width respectively below 50% and within 100ms, and effectively restrains the three-phase imbalance, rendering superior reliability and stability, With the response time smaller than 3ms it can solve the defects of traditional shunt capacitors and well satisfy the requirements on the quality improvement of electric energy and energy-saving application of power distribution network. Our Solutions Advanced Static var generator APF+SVG ZDDQ MEC Products Adanced static var generator Low voltage static var generator and active power filter system Advanced Static Var Generator static var generator and active harmonic filter system Advanced SVG The Advanced Static Var Generator provides the same dynamic performance as the SVG with the added benefit of combining harmonic mitigation. Available in 50/100/150,kVar wall mount and 100/150kVar cabinet mount modules, 400/480/690VAC three phase Extend your Power Factor Correction Performance The requirement for power factor correction is the number one power quality issue faced by the vast majority of industrial and commercial installations. The second biggest power quality issue is harmonic mitigation. Commercial installations will often have elevated 3rd harmonics owing to single phase non-linear loads such as computer switch mode power supplies, LED lighting, electronics lighting ballasts, inverter heat pumps. Add a computer data centre backed up by UPS containing a six pulse rectifier and 5th, 7th, 11th harmonics can be added into the mix. Variable Speed Drives controlling air handler units within building HVAC systems can further elevate the 5th, 7th, 11th harmonics Industrial installations will often have high levels of variable speed drive loading as automation systems improve efficiencies and productivity. It is no uncommon to see very high levels of current harmonics and voltage harmonic distortion resulting from six pulse VSDs drawing predominantly 5th, 7th 11th harmonics. Wouldn’t it be great if you could address both power factor correction and harmonic mitigation in one cost effective unit. The Advanced Static Var Generator (ASVG) does just that. Power Factor Correction And Harmonics Filtering in One Unit Reactive power compensation: Cos ϕ = 1.00 Capacitive and Inductive compensation: -1 to +1 All the features and benefits of the SVG Mitigation of 3rd, 5th, 7th, 11th harmonic orders Unit capacity can be shared 50/50 between power factor correction and harmonics correction Current imbalance correction can correct for load imbalance across all three phases The 3rd, 5th, 7th, 11th harmonic orders are the most prevalent in the majority of installations. A correctly sized ASVG can not only correct your displacement power factor to unity but also reduce your harmoni...
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  • Integrated Capacitors

    Integrated Capacitors

    Low voltage intelligent power capacitor This is a new generation of energy-saving reactive power compensation device which can effectively reduce capacitor loss/wastage of coil, improve power factor and electrical quality in 0.4KV low voltage network. This product onsists of intelligent measurement and control unit, passing zero switch, rpotection unit and 2 triangle type /1 Y type LV power capacitor. Heavy structure and bulky size no longer exist, the product is smaller, easy to do maintenance,lower loss and longer lifetime with better price. Meet high requirement of modern intelligent power network to power compensation. Main functions Filtration function Function of Switching without surge Respective compensation function Measurement Protection function Signaling function Communication function Connection function Intelligent network control Self-diagnosed function What we offer ◆Integrated Capaicotrs with Thyristor ◆Intergrated Capacitors with Combination switch ◆Intergrated Capacitors with Contactors Remark:Reactors optional
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  • Power Quality

    Power Quality

    Power Quality Power quality refers to the ability of electrical equipment to consume the energy being supplied to it in an efficient and effective manner. A number of power quality issues including electrical harmonics, poor power factor, voltage instability and imbalance impact on the efficiency of electrical equipment. This has a number of consequences including: Higher energy usage and costs. Higher maintenance and repair costs. Equipment instability and failure resulting in process or business disruption. How is your Power Quality? Power Quality – the efficiency and effectiveness of power supply. Good power quality is critical in efficient and uninterrupted industrial processes. Poor power quality can result in unstable equipment operation or failure, inefficiencies and reduced equipment lifespan, interruption of supply and plant down-time. ZDDQ specialise in evaluating, auditing and addressing a wide range of power quality issues to increase plant, motor and equipment efficiencies and the bottom line. What solution is right for us? Power consumption can be influenced by an intricate and complex set of variables. Our deep knowledge of power supply and electrical systems allow us to pinpoint your requirements as a power user and design or assign a solution that addresses your needs. This is generally done in 2 ways: By understanding your power usage and any problems that may be occurring, our experienced people will recommend the right solution. ZDDQ can perform a full power audit including data logging over a set period of time. This can allow an intimate knowledge of your power profile allowing us to develop a cost benefit analysis against a range of technologies of combination of technologies. Our Technologies and Solutions are Varied Power Quality products can be sorted in five general categories 1. Active Power Filters Active power filters (APF) are devices connected in parallel with the load to be compensated. They can be understood as controlled current sources that provide any kind of current waveform (in terms of phase, amplitude and frequency) in real time . APF are flexible, high performance and cost-effective solutions used to mitigate all the power quality problems generated by the equipment installed in electric power systems, enhancing equipment operating life time, and improving power system capacity.Active Power Filter products include: Active Harmonic Filters (AHF) Static VAR Generators (SVG) Active Load Balancers (ALB) Hybrid VAR Compensators (HVC) 2. Power Factor Correction Power Factor Correction (PFC) aims to improve power factor and hence power quality, switching in capacitors to offset usually inductive loads, for example electric motors. PFC systems increase the efficiency of power supply, delivering immediate cost savings on electricity.Technologies in this group include: Power Factor Correction (PFC) Smart Power Factor Correction Static VAR Generators (SVG) Hybrid VAR Compensators (HVC) 3. Static Compensators(SVG and...
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    Energy Saving Everyone wants to save money on their energy bill. Many facilities have mandates to save energy. Improving energy efficiency offers huge advantages to businesses—reducing the costs of energy and operations— and increasing sustainability. Reduced power costs can be achieved by reducing the voltage received and increasing the quality of the power. ZDDQ develop technologies to achieve efficiencies for industrial and commercial high energy users through standardised and customised solutions. Reduce power consumption and reduce your costs and environmental footprint. Technologies for reducing Electricity Bill, ◆Power factor correction(PFC) – by reducing reactive power consumption ◆Active Hamonic Filter– by eliminating unwanted harmonics ◆Static VAR Generators(SVG) – through creating efficiencies by adapting to fast changing loads   Save money by saving energy One of the best ways to save money on an electric bill is to reduce the amount of energy used in a facility, either through the use of energy-efficient devices, or through intelligent building control systems. Energy-efficient devices can range from variable frequency drives (VFDs) for motor control, to utilizing LED lighting, or high-efficiency motors and transformers. Intelligent building controls can leverage new or existing technology to reduce energy consumption through load management, lighting control and advanced thermostats. This section will explore, in detail, the methods available to save money through directly reducing energy consumption in facilities. Three main load types dominate electricity use in commercial facilities. HVAC, lighting and plug loads (office device and computers) combine to represent almost 85% of all electric energy consumed by commercial customers.
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