Abstract:
A system and method for providing power to critical from a plurality of sources. The system provides a means of eliminating harmonics generated by loads from being conducted into the power source(s). Additionally, the system provides power conditioning to sags, surges and spikes produced by incoming sources. Power quality and system status monitoring and control are provided via communication mean such as the Internet.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is a continuation-in-part application of, and claims priority to, U.S. application Ser. No. 09/955,405, filed on Sep. 12, 2001. 
     
    
     
       TECHNICAL FIELD  
         [0002]    This invention relates to a system for improving power quality and distribution, and more particularly to a power quality system including a harmonic cancellation unit.  
         BACKGROUND  
         [0003]    Modem electronic systems present conflicting requirements to power providers and the distributions systems they serve. On the one hand, many of the computer and telecommunication systems being brought on-line today present non-linear loads to the source that serves them. These non-linear loads reduce the quality of power locally and else where on the grid. Additionally, the non-linear loads result in wasted power and increased wiring requirements. On the other hand, many of these same loads are intolerant of the very quality problems that they create. Therefore there is a need for systems that reduce the disturbances created by the load while simultaneously improving the power to such loads.  
           [0004]    One of the most common nonlinear loads is the input of a DC/DC converter on a personal computer or a telecommunications power supply. Typically composed of an input rectifier followed by smoothing capacitor, these systems draw current from the source at the peaks of the input voltage waveform. The result is a current waveform with a significantly higher RMS value than a linear load drawing the same power. This higher current in turn drives power systems to be designed with larger generation and distribution capacity.  
           [0005]    Additional issues that arise due to non-linear loads are distortion of the voltage waveform on the power grid at locations close to such loads. Because power grids are not designed to accommodate the large number of non-linear loads that are on-line today, the system impedance causes voltage drops at the extremities of the power grid.  
           [0006]    Systems to accomplish these goals are seen in U.S. Pat. Nos. 5,343,080 and 5,434,455. These systems describe two (or more) secondary windings on the transformer to accomplish the cancellation of harmonics. The secondary windings must, to some extent, share the load. This places a significant burden on system maintenance. When loads are removed the system must be rebalanced to provide the appropriate harmonic cancellation attribute.  
           [0007]    Similarly, such systems must be tuned to address specific load generated harmonics. This consists of physically changing the output connections of the transformer. In addition to the setup time required to implement such a system, this same problem presents itself when loads are removed or replaced by others with different characteristics.  
           [0008]    The filters that are part of the above referenced patent also do not address the issue of harmonic currents in the neutral connection. Harmonic currents, which can significantly exceed the phase currents, are by-products of nonlinear loads. Harmonic currents in the neutral connection significantly increase the cost of system wiring. For example, for three-phase power, the wiring may be increased, as much as twice in diameter, to accommodate an unbalanced load. In older buildings that were not designed for modern power requirements, heating problems in existing neutral connections can present safety issues, like fire as a result of the fact that unbalanced loads for three-phase power can significantly increase neutral currents and resistance heating.  
         SUMMARY  
         [0009]    The present invention addresses the shortcomings of present day power systems with a harmonic cancellation transformer having a filter, transfer switch, disconnection devices and surge suppression devices. These components can be combined in various ways to form systems that protect the critical load from a range of power quality events, e.g., from black outs to surges due to lightning. Additionally, these components combine to present a load to the power source that has significantly reduced levels of harmonic distortion.  
           [0010]    The harmonic cancellation transformer includes a single secondary winding that can be wound to cancel the third and triplen harmonics of the excitation frequency. These harmonics represent a significant component of harmonic distortion in most systems. The transformer attenuates these harmonics in the primary and therefore on the power grid. When triplen harmonics are cancelled, the power grid is advantageously cleaner.  
           [0011]    The filter in the secondary of the transformer can serve several functions. First, harmonics that may be present in the secondary circuit are attenuated—this can include all harmonics, not just the triplen harmonics. Second, the filter attenuates these harmonics in the secondary circuit thereby mitigating their deleterious affects and reducing the amount of wiring necessary, for example, in the neutral connections. Coupled with the single secondary form of the harmonic transformer, the system requires only one filter element. Typically downstream of filter, the transient suppression components provide protection to the load from over voltage events on the primary side.  
           [0012]    In one embodiment of the invention, a harmonic cancellation unit is connected to a uninterrupted transfer switch (UTS). The transfer switch provides appreciably uninterrupted power from a plurality of sources. The UTS is setup to automatically switch from the presently utilized source to an alternate source in a time span short enough to be undetectable to sensitive loads. In this configuration, the harmonic cancellation unit further improves the power quality received by the load. Control and remote monitoring can be included to further improve system performance and flexibility.  
           [0013]    The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. 
       
    
    
     DESCRIPTION OF DRAWINGS  
       [0014]    [0014]FIG. 1 schematically depicts an Advanced Power Distribution System, according to the present invention.  
         [0015]    [0015]FIG. 2 schematically depicts an Advanced Power Distribution System including an Uninterruptible Transfer Switch (“UTS”) and a Harmonic Cancellation Module.  
         [0016]    [0016]FIG. 3 schematically depicts a Harmonic Cancellation Unit including a Zig-Zag transformer with common mode and differential mode passive filters for use in Power Distribution Systems.  
         [0017]    [0017]FIG. 4 schematically depicts a Harmonic Cancellation Unit including a Delta-Wye transformer with common mode and differential mode passive filters for use in Power Distribution Systems. 
     
    
     DETAILED DESCRIPTION  
       [0018]    [0018]FIG. 1 illustrates an embodiment of an Advanced Power Distribution System  100  according to the present invention. The Advanced Power Distribution System  100  can include a primary  101  and alternate source(s)  102 , protective devices  212 , Harmonic Cancellation Module  214 , Lightning/Surge protector  216 , disconnects  218 ,  220 , and  224 , transfer switch  10 , remote monitoring (GRAM)  118 , control module  116 , Transient Voltage Surge Suppressor (TVSS)  230 , load distribution  228 , and the critical load(s)  232 .  
         [0019]    Sources  101 ,  102  or  103  may include power from a utility company, or generated power from diesel generators, fuel cells, nuclear power plants, and other well known sources. This power is then fed into the transfer switch  10 . The transfer switch  10  is used to transfer between any one of the sources. This allows power from the alternate source(s) to be switched to the critical load(s)  232  in the event the preferred source  101  exhibits a loss of power. The transfer switch  10  can be a SCR, Triac, IGBT, Relay, Contactor, an Uninterruptible Transfer Switch (UTS), or other well known transfer switch.  
         [0020]    The output of the transfer switch  10  is connected to the primary of the Harmonic Cancellation Module  214  through disconnect device(s)  224 . As described further below, the Harmonic Cancellation Module  214  attenuates harmonics in the Advanced Power System  100 . This can be accomplished, for example, by use of a transformer and appropriate filters (not shown) as described further below. Protective devices  212  protect the system from harmful electrical failures, e.g., short circuit conditions caused by the critical loads  232 , or by a transformer short, or from a failed transfer switch  10 . Device(s)  212  and  224  could be circuit breaker(s), fuse(s), vacuum breaker(s) or other well known current limiting device(s).  
         [0021]    Lightning/Surge Arrestor  216  is a device that shunts high energy/noise pulses into the grounding system of the building. For example, exemplary devices are capable of handling currents of 40 kA or greater. For example, Lightning/Surge Arrestor  216  can be Metal Oxide Varistors (MOV&#39;s), lightning arrestors, active clamping devices, or other well known clamping devices.  
         [0022]    Disconnects  220  and  224  are used to provide a maintenance mechanism to allow power to be diverted around the transfer switch  10 , for example, in the event of failure. Transient Voltage Surge Suppressor (TVSS)  230  is a device that shunts energy/noise pulses between line and neutral connected to the critical load  232 . Typically, this device is capable of handling currents of 500 A or greater. These devices can include Metal Oxide Varistors (MOV&#39;s), lightning arrestors, active clamping devices, or other well known clamping devices.  
         [0023]    Load distribution  228  allows a plurality of critical loads  232  to be connected to the system  100 . The load distribution  228  allows single phase loads, dual phase loads, as well as three phase loads to be connected to system  100 . This can be achieved, for example, by single molded case switches or circuit breakers or by combinations of  42  pole panels.  
         [0024]    [0024]FIG. 2 depicts another embodiment of the Advanced Power Distribution System  100 . While shown as single lines, the power sources  101 ,  102 ,  103  can be multi-phase or single-phase. Switches  110 ,  111 ,  112  isolate each of the power sources from the load  232 . A source designated as the “preferred source”  101  is the power source that will be selected by the transfer switch  10  as long as the preferred source  101  meets certain predetermined power quality requirements such as amplitude, phase, and frequency stability. In this embodiment, the transfer switch  10  is an Uninterruptible Transfer Switch (“UTS”), which means that the load  232  will not experience an appreciable voltage outage during switching of the power sources. Protective devices and lightning/surge protectors (not shown) can be added between the power sources and the load  232  to protect the load  232  from transient events that may occur up-stream of the UTS  10 .  
         [0025]    A choke  119  is in-line with the load  232 . The choke  119  is typically a passive, low loss, element that performs no significant function during normal operation of the UTS  10 . The choke  0 . 119  can pass current from the selected source to the load. The choke  119  may be a standard choke or a coupled inductor. The choke can also be replaced with any of a variety of well-known transformers used in power applications, like isolation transformers.  
         [0026]    Rectifiers  107 ,  108 , and  109  are coupled to the source side of the switches  110 ,  111 ,  112 . During normal operation, i.e., non-transient power conditions, any of the rectifiers  107 ,  108 ,  109  can feed an inverter  114  from any power source, typically one with the highest voltage. Because the inverter  114  can be controlled in the manner described below, in a low power, “stand-by” state, the current passed through the rectifiers can be minimal and therefore power dissipation is advantageously low. During stand-by operation, the inverter  114  can also be used to regulate voltage to the load  232  and used to improve power factor of the load  232 . When the power sources are being switched, i.e., during transient conditions, the inverter  114  is used provide power to the load  232 .  
         [0027]    The inverter  114  input can include a bank of electrolytic capacitors (not shown) used in conjunction with the rectifiers to sufficiently “smooth” the input voltage to the inverter  114 . During normal operation, the inverter  114  maintains a sinusoidal voltage at the output of filter  115  and the auto transformer  117  substantially equal in amplitude at the load  232 . Therefore, the aggregate affect of the UTS  10  on system power during normal operation is minimal.  
         [0028]    Referring again to FIG. 2, the system  100  can include the addition of energy storage element  121 . Energy storage element  121  provides energy to the inverter independent of all sources. In this way, the energy storage element  121  enables the system to “ride-through” instances when none of the power sources are able to provide power to the load. In this way, the system can be configured so that the alternative power source need not be readily available, for example, an engine-driven generator or turbine. Thus, the energy storage element  121  can provide energy to the inverter while and until the alternative source is able to generate power. Energy storage element  121  can consist of any well-known components, e.g., generator, turbine, electro-chemical capacitors, double layer capacitors, battery, electrolytic capacitors, hybrid capacitor/battery, fuel cell, super capacitor, HED (high energy-density) capacitor, etc. For example, the battery can be any well known type like lead acid, lithium, NiCAD, NiMH, etc.  
         [0029]    Control module  116  can control the operation of the system  100 , including switches  110 ,  111 , and  112 . The control module  116  can sense power quality from the sources  101 ,  102 ,  103  as well as their respective power output quality, for instance, voltage, current, phase and frequency. For example, using DQ transformation as well as individual line-line criteria, the power quality of all of the input power sources can be monitored by control module  116 .  
         [0030]    Operators can program the control module  116  to operate elements of the UTS  10  and the Harmonic Cancellation Unit  214  in accordance with the requirements of the load  232 . That is, such programs can be altered depending upon the system operational requirements of the load  232 , for example, how sensitive the load  232  is to changes in power quality. When the power quality of the presently utilized source falls outside of user-determined bounds for a predetermined time period, the control module  116  can initiate the process of switching to another source. For that reason, the control module  116  is coupled to and can control actuation of switches  110 ,  111 , and  112 . Because the control module  116  can monitor all sources, an alternate source can be identified at all times. Software to facilitate the functions of control module  116  can reside in numerous places in system  100 , including remote monitoring  118  and control module  116 .  
         [0031]    The control module  116  can also monitor power quality coming into the inverter  114 . Likewise, the control module  116  can monitor power quality coming out of the inverter  114  (not shown). This may be particularly useful in controlling the operation of the inverter  114  so that power quality, like voltage, current, frequency and phase is monitored and maintained by controlling the operation of the inverter  114 . The control module  116  can also activate, operate and deactivate the inverter  114 . The control module  116  can also monitor and control the operation of the energy storage element  121 .  
         [0032]    The control module  116  can also monitor power quality input to the load  232 . This will help the control module  116  to prevent undesirable power quality from reaching the load  232 . Those of skill in the art will appreciate that the control module  116  can perform additional functions like maintenance and diagnostic functions of any or all system  100  elements. For example, the control module  116  can include memory functions to keep a history of the Advanced Power Distribution System  100  operation and the associated variables.  
         [0033]    Referring again to FIG. 2, remote monitoring unit  118  can be coupled to any and all components of the system  100 . During all modes of operation, the remote monitoring unit  118 , also referred to as GRAM (Global Remote, Advanced Monitoring) provides the functions of remotely monitoring and/or controlling system  100 , including UTS  10  and Harmonic Cancellation Module  214 . Remote monitoring unit  118  can transmit and/or receive system  100  information concerning some or all of the system  100  state variables, for example, operating amplitudes, frequencies, integrity of system components, availability and selection of power sources, and power quality including, but not limited to input voltage, input current, input power (watts, VA, VARS), input voltage distortion, input current distortion, input THD, input Power Factor, input surge events, input brown outs, input black outs, output voltage, output current, output power (watts, VA, VARS), output voltage distortion, output current distortion, output THD, output Power Factor, output surge events, brown outs, black outs. GRAM  118  can also be utilized to control or change some or all of the system  100  state variables, including but not limited to UTS  10  and Harmonic Cancellation Module  214  state variables, like inverter  114  operation, source selection, harmonic frequency attenuation or excitation, etc. GRAM  118  can transmit and receive this information to external remote devices to allow control and monitoring of the system  100  using any well-known communication technology, e.g., satellite link, cellular link, telephone link, etc. Additionally, GRAM  118  can communicate to remote devices like laptop computers or similar devices, via several different communication protocols such as TCP/IP, MODBUS, etc.  
         [0034]    For example, once the control module  116  has detected an out of specification condition in the preferred source  101 , e.g., transient power condition, the control module can initiate steps directed to changing power sources without appreciable interruption in power supplied to the load  232 . A signal from the control module  116  can trigger the inverter  114  to active mode. During the normal state, the inverter  114  can be in a standby mode passively synchronized to the power source.  
         [0035]    Upon receipt of the command to control output voltage, for example from the control module  116 , the inverter  114  draws power from the one or more of the rectifiers  107 ,  108 ,  109  and begins furnishing power to the load  232 . Following activation of the inverter  114 , the control module  116  can issue a command resulting in the opening of switch  110  thereby disconnecting the failing source  101  from the load  232 . In a like manner, the control module  116  can monitor and control the operation of the Harmonic Cancellation Module  214  in order to provide power to load  232  in accordance with the invention. For example, the control module  116  can detect degraded power quality, for example by the presence of undesired harmonic frequencies or out of specification in neutral currents. Likewise, the control module  116  can actuate, for example, variable components in filters  364  and/or  366  to attenuate the unwanted harmonics thereby improving system  100  performance so that load  232  receives improved power quality.  
         [0036]    Embodiments of the Harmonic Cancellation Module  214  are depicted in FIG. 3 and FIG. 4. Physical construction of the transformer, core, coils, and filters are not shown as this is well understood by those skilled in the art. FIG. 3 describes the Harmonic Cancellation Module  214  that can attenuate triplen harmonics. Triplen harmonics are odd harmonics which are the odd multiples of the third harmonic, e.g., 3 rd , 9 th , 15 t , 21 st , etc. The Harmonic Cancellation Module  214  depicted in FIG. 3 also attenuates the 5 th , 7 th , 11 th  harmonics. These harmonics are attenuated by the combination of the transformer  502 , common mode filter  366 , and differential mode filter  364 .  
         [0037]    The transformer  502  is constructed utilizing three phase primary input windings  308 ,  310 ,  312 , configured in a Delta configuration, with multiple taps, and three phase output windings  314 ,  316 ,  318 ,  320 ,  322 ,  324  configured in an interconnected star (“Zig-Zag”) winding. The windings for both the primary and secondary windings can be constructed by any well known means, for example from copper, aluminum, wire or foil.  
         [0038]    The windings are placed on a core structure  370  that can be made from steel, silicon steel, amorphous metal or other well known magnetic materials. Core structure  370  can be either a single structure, or three separate structures. The primary Delta configuration shown is wired by connecting one end of coil  308  to one end of coil  310 , and one end of coil  310  to one end of coil  312 , and finally by connecting one end of coil  312  to one end of coil  308  as depicted in FIG. 3. The three phase inputs  302 ,  304 ,  306  are connected to the primary windings  308 ,  310 ,  312  as shown in FIG. 3. The interconnected star winding (Secondary) is arranged in core structure  370  by phase shifting the secondary windings, allowing the triplen harmonics to be eliminated from being induced into the primary winding. The secondary winding is configured by sharing the individual phase windings in different legs of the core structure  370 .  
         [0039]    ‘Phase A’ output of the transformer is connected as follows: Coil  314  is wound on the ‘Phase A’ leg of the core  370  and coil  320  is wound on the ‘Phase B’ leg of the core  370 . One end of coil  314  is connected to one end of coil  320  at  326 . The other end of  314  is connected to the neutral output of transformer  502 , along with coil  318 , and coil  322 . The phase output of the transformer for ‘Phase A’ is connected from one end of coil  316  to one end of inductor  344 .  
         [0040]    ‘Phase B’ output of the transformer is connected as follows: Coil  318  is wound on the ‘Phase B’ leg of the core  370  and coil  324  is wound on the ‘Phase C’ leg of the core  370 . One end of coil  318  is connected to one end of coil  324  at  330 . The other end of  318  is connected to the neutral output of transformer  502 , along with coil  314 , and coil  322 . The phase output of the transformer for ‘Phase B’ is connected from one end of coil  320  to one end of inductor  340 .  
         [0041]    ‘Phase C’ output of the transformer is connected as follows: Coil  322  is wound on the ‘Phase C’ leg of the core  370  and coil  316  is wound on the ‘Phase A’ leg of the core  370 . One end of coil  322  is connected to one end of coil  316  at  328 . The other end of  322  is connected to the neutral output of transformer  502 , along with coil  314 , and coil  318 . The phase output of the transformer for ‘Phase C’ is connected from one end of coil  324  to one end of inductor  348 .  
         [0042]    The transformer  502  alone can only effectively cancel triplen harmonics as described earlier, and only with balanced loads. The Wye connected loads contribute a large percentage of 3 rd  harmonics in which transformer  502  can cancel from the secondary to the primary windings. However, these harmonics, known as zero sequence harmonics, add up in the neutral conductor of the secondary circuit, and as such must be rated for at least 1.73 times the line current. These currents have been known to overheat transformers, as well as building wiring, and associated protective devices. With modem power systems, it is hard for the end user to ensure that the loads are connected to balance the output seen by the secondary winding of transformer  502 , as these loads could be a plurality of single phase loads. In order to handle the imbalance of the three phase output, and to attenuate the harmonics in the neutral side of the loads, one embodiment of the invention includes a filter  364  as part of the Harmonic Cancellation Module  114 .  
         [0043]    The filter  364  effectively attenuates the 3 rd  harmonic in the neutral line. However, it should be noted that the filter is capable of being tuned to this and other harmonics. As depicted in FIG. 3, the filter  364  is a three pole, L/C type, band reject filter. The 3 rd  harmonic is attenuated by filter components, capacitors  338 ,  340 ,  342  and inductors  332 ,  334 ,  336 . The values of these components can vary based on the design requirements, and available components. Typically, these values can be selected by determining the desired corner frequency calculated from the equation fc=(½π) Square Root(LC), where L is the inductance and C is the capacitance. The inductors  332 ,  334 ,  336  can be made of different core materials such as ferrite, iron, powdered iron, steel, silicon steel, amorphous metals, and other know materials. The inductors  332 ,  334 ,  336  could also be a single inductor, or a plurality of inductors to make the desired inductance. The capacitors  338 ,  340 ,  342  can be of different materials such as polyester, metalized polyester, polycarbonate, metalized polycarbonate, oil filled, paper, ceramic, mica, or other well known materials. The capacitors  338 ,  340 ,  342  could also be a single capacitor, or a plurality of capacitors to make the desired capacitance. The tuned filter diverts the unwanted harmonic neutral current into the ground conductor  372 , thus attenuating unwanted harmonics, reducing the amount of the particular harmonics making the neutral current equal to or less than the line current.  
         [0044]    Load  232  can predominantly generate the 5 th , 7 th,  and 11 th  harmonics. These harmonics do not return to the neutral, and are not treated by filter  364  or by transformer  502 . In order to attenuate and treat these harmonics, filter  366  can be employed. Filter  366  can be designed to effectively attenuate harmonics greater than 250 Hz, and frequencies greater than 250 Hz are typically attenuated at 40 dB/decade. However, it should be noted that filter  366  is capable of being tuned to this and other frequencies. Filter  366  can be a L/C type, low pass filter as shown in FIG. 4. Components in the filter  366  attenuate harmonics. The components include capacitors  350 ,  352 ,  354  and inductors  344 ,  346 ,  348 . As discussed above in relation to filter  364 , the values of these components can vary based on the design requirements, and available components. Typically, these values can be selected by determining the desired corner frequency calculated from the equation fc=(½π) Square Root(LC), where L is the inductance and C is the capacitance. The inductors  344 ,  346 ,  348  can be made of different core materials such as ferrite, iron, powdered iron, steel, silicon steel, amorphous metals, and other know materials. The inductors  344 ,  346 ,  348  could also be a single inductor, or a plurality of inductors to make the desired inductance. The capacitors  350 ,  352 ,  354  can be of different materials such as polyester, metalized polyester, polycarbonate, metalized polycarbonate, oil filled, paper, ceramic, mica, or other well known materials. The capacitors  350 ,  352 ,  354  could also be a single capacitor, or a plurality of capacitors to make the desired capacitance. The tuned filter attenuates load generated harmonics from conducting into the secondary of transformer  502 , thus attenuating these harmonics from being seen on the primary side of transformer  502 .  
         [0045]    Although filters  364  and  366  are depicted as passive elements, those of skill in the art will appreciate that these filters can employ active elements, e.g., microprocessor controlled adjustable filters. In this way, the filters  364  and  366  can be arranged to create adjustable filters that can have variable characteristics, like frequency cutoffs. This is advantageous in applications where unwanted harmonics and neutral currents vary and therefore filters  364  and  366  can be optimized “on the fly” to respond to transient conditions thereby optimizing power quality delivered to load  232 . As described earlier, control module  116  and/or remote monitoring  118  can be utilized to adjust the Harmonic Cancellation Module  214 .  
         [0046]    [0046]FIG. 4 depicts another embodiment of the Harmonic Cancellation Module  214  which can attenuate harmonics as in FIG. 3, with an exception. Transformer  504  does not attenuate triplen harmonics. The construction of transformer  504  is similar to the construction of transformer  502  of FIG. 3 except for the connection of the secondary windings. ‘Phase A’ output of the transformer is connected as follows: Coil  304  is wound on the ‘Phase A’ leg of the core  370 . One end of coil  404  is connected to the neutral output of transformer  504 , along with coil  406 , and coil  408 . The phase output of the transformer for ‘Phase A’ is connected from one end of coil  404  to one end of inductor  344 .  
         [0047]    ‘Phase B’ output of the transformer is connected as follows: Coil  406  is wound on the ‘Phase B’ leg of the core  370 . One end of coil  406  is connected to the neutral output of transformer  504 , along with coil  404 , and coil  408 . The phase output of the transformer for ‘Phase B’ is connected from one end of coil  406  to one end of inductor  340 .  
         [0048]    ‘Phase C’ output of the transformer is connected as follows: Coil  408  is wound on the ‘Phase C’ leg of the core  370 . One end of coil  408  is connected to the neutral output of transformer  504 , along with coil  404 , and coil  406 . The phase output of the transformer for ‘Phase C’ is connected from one end of coil  408  to one end of inductor  348 .  
         [0049]    Referring again to FIG. 2, and as discussed above, control module  116  interrogates the system  100  for power quality including, but not limited to input voltage, input current, input power (watts, VA, VARS), input voltage distortion, input current distortion, input THD, input Power Factor, input surge events, input brown outs, input black outs, output voltage, output current, output power (watts, VA, VARS), output voltage distortion, output current distortion, output THD, output Power Factor, output surge events, brown outs, black outs. The control module  116  transmits this information to remote monitoring (GRAM)  118  so that system  100  can be remotely monitored and/or controlled. Additionally, as discussed above, software can be incorporated into both control module  116  and remote monitoring  118  so that the system automatically controls system  100  to compensate for any and all preprogrammed out of specification conditions. Likewise, remote monitoring  118  can be utilized to download upgraded software remotely, altered system  100  performance specification criteria remotely, or like information remotely thereby resulting in a more manageable and dynamic system  100 .  
         [0050]    The control module  116  and remote monitoring  118  can interrogate the system  100  to include but not limited to temperature conditions of transformers in Harmonic Cancellation Module  214 , status of disconnects  220  and  224 , status of protective device(s)  212 , lightning surge protector  216 , transfer switch  10 , voltages and currents associated with load distribution  228 , and status of transient voltage surge suppressor  230 . The control module  116  and/or the remote monitoring  118  can include storage media to store data concerning the performance of system  100 . As discussed above, the remote monitoring  118  can transmit the system  100  performance data via the internet, phones lines, fiber optic lines, wireless means, or by any well known communication media.  
         [0051]    A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention.