GB2479519A

GB2479519A - Apparatus for coupling to a mains electrical supply for reducing the reactive, apparent and also the real power components

Info

Publication number: GB2479519A
Application number: GB201001905A
Authority: GB
Inventors: John Albert Wilkins
Original assignee: ECOTEK UK Ltd
Current assignee: ECOTEK UK Ltd
Priority date: 2010-02-05
Filing date: 2010-02-05
Publication date: 2011-10-19
Also published as: GB201001905D0

Abstract

Power perfector (power factor correction) apparatus for coupling to a domestic electrical mains supply, and supplying mains power to a variety of electrical appliances. The mains supply includes a reactive power component (Q), an apparent power component (S), a real power component (P) and a load component, whilst the invention is reported to reduce all three components, including the real component. The apparatus comprises mains coupling means, for example a two or three pin plug (figure 7) and at least one parallel capacitor C604. In one embodiment the capacitor has a large bleed resistor 605 of 1 MQ placed across the capacitor to discharge the capacitor when removed from the mains. In addition the apparatus has a voltage dependent resistor 606 which is included for protection against high voltage transients on the mains supply. The voltage dependent resistor 606 can be a metal oxide resistor. The apparatus may also include a series fuse to protect the circuit from an over current transient. The apparatus may also include a light or LED 802 for illumination, and an adjustable series resistor 1002. Alternatively the device may be placed in a domestic appliance. The mains coupling means and the at least one capacitor 604 are connected to one another in parallel and, in use, the apparatus reduces the real power (R) of the mains supply component by reducing both the reactive power (Q) and the apparent power (S) components.

Description

IMPROVED ELECTRICAL CIRCUIT

Field of the Invention

The present invention relates to an improved electrical circuit. More particularly, the present invention relates to a device for improving the power characteristics of a domestic electrical circuit.

Background to the Invention

Electricity in an electricity supply system with loads comprises three components, the real power measured in watts, the apparent power measured in voltamperes and reactive power, measured in reactive voltamperes. A characteristic of an electricity supply system is the power factor, defined as the real power divided by the apparent power. The power factor of an electricity supply network having one or more loads connected thereto is defined as the ratio of the real power, which is the electric power actually producing an affect, to the apparent power, which is the power actually fed to the device requiring or implementing the effect, i.e. the load.

When the power factor is equal to zero, the electricity flow in the network is entirely reactive, wherein any energy stored in a load returns to the source on each cycle.

Conversely, when the power factor is one, all the electrical energy supplied by the source is consumed by the load. The power factor is therefore a number varying between plus and minus one, abbreviated as ±PF, and which is traditionally close to one in domestic environments, having comparatively fewer inductive or capacitive elements relative to industrial or commercial environments.

Power factor correction techniques have long been implemented in industrial and commercial environment for adjusting the power factor to near one, usually at the requirement of electricity -producing utility companies and/or as a result of regulatory requirements. A power factor inferior to one require a utility to generate more than the minimum apparent power necessary to supply the real power, which unduly increases the costs of producing and transmitting electricity.

** Known techniques for power factor correction usually involve the commission and installation of a power factor correction unit in an industrial environment having one or more inductive or capacitive loads, consisting of a number of capacitors that are switched with contactors, which are themselves controlled by a regulator which measures the power factor in the electrical network. Such power factor correction units are quite onerous and their commissioning and implementation is a function of the extent of the correction required, commensurate with the scale of the loads in a relevant commercial or industrial setting.

Because domestic environment have long been considered very close to the value 1, there is a long-standing disinterest and disincentive to consider power factor correction as one of a number of solutions for optimizing domestic electricity consumption.

Figure 1 illustrates a number of typical loads to be found in a domestic setting 100, which is connected to an electricity supply system (not shown), the power of which is made accessible by a number of mains supply outlets 101. Within a domestic setting, any number of electrical appliances may be connected to a mains supply outlet 101, some of which may be more resistive than others. For example, a kettle 102 and a filament lamp 103 comprise electrical circuits containing purely resistive elements having a power factor of, or closest to, 1. A television 104 and a mobile phone charger 105 contain capacitive elements having a power factor somewhat inferior to 1. A fridge freezer 106, a washing machine 107 and a tumble dryer 108 comprise circuits containing inductive and/or capacitive elements having a power factor likewise inferior to 1, substantially so in the case of the washing machine and the compressor of the fridge freezer.

A schematic representation of an electrical circuit typically found in the example domestic environment 100 is provided in Figure 2, wherein the circuit 201 is connected to an electrical power mains supply 202, for receiving alternative current (AC) therefrom. The S. circuit is provided with a general mains switch 203 for allowing the supplied AC power to flow through circuit 201 or interrupting the AC power supply. The overall domestic load is shown at 204 and comprises the appliances 102 to 108 when in use. The overall *.: 30 resistance in the circuit is shown as 205, which comprises the resistive component of each of appliances 102 to 106, if any, and the resistive component inherent to the structure of *:*::* circuit2Ol. S..

* Appliances 102 to 108 are usually connected to circuit 201 in parallel, for permitting the ad hoc supply of power thereto on a permanent or temporary basis, independently of one another. With reference to Figure 3, the domestic load 204 therefore comprises a variable number of domestic appliances at any one time, such as those illustrated in Figure 1, each of which is equipped with a respective on/off switch, noting that each socket 101 to which an appliance is connected to may itself be equipped with fts own on/off switch to enable or interrupt mains power supply at the source rather than at the appliance. The schematic representation of load 204 therefore includes a respective mains switch 302 for kettle 102, a mains power switch 304 for television 104, and so on and so forth.

The alternative current power flow in circuit 201 includes the three components, real power (P) measured in watts (W), apparent power (S) measured in voltamperes (VA) and reactive power (0) measured in reactive voltamperes (Var), and a schematic representation of the relationship binding these three components is shown in Figure 4.

The power factor, the notation of which is ±PF, is the ratio of the real power (P) and the apparent power (S).

The relationship illustrated in Figure 4 at the scale of the entire domestic environment 100, therefore the entire circuit 201, represents the combination of the respective portions of real, apparent and reactive power components attributable to each electrical appliance 102 to 108, as schematically illustrated in Figure 5. Reprising the specific example described in relation to Figure 1, fridge freezer 106 is shown as generating a comparatively much larger positive reactive power component (Q1) for a lesser amount of real power (P1) drawn, relative to the positive reactive power component (Q2) and real power component (P2) attributable to kettle 102.

The long-standing developments in power factor correction within industrial and *1* commercial environments are grounded in the fact that power metering for these environments, particularly those comprising industrial loads, is performed on both the real (P) and the reactive (Q) component of supplied power, wherein an elevated reactive *:*. 30 component (caused by an unoptimised power factor) is charged at a premium. Known * PFC circuits or devices are used in this context to lower the amount of reactive power (0), * ** leaving the real power (P) unchanged, thereby sparing industrial and commercial users from reactive power-related financial penalties. * *. *

Comparatively, the lack of corresponding power factor correction within the domestic context can be explained by the fact that utility companies in many jurisdictions, for instance the United Kingdom, traditionally measure and invoice domestic consumers on only the real component (P) of supplied power. In the domestic context therefore, a PFC circuit or device appears redundant, since it is expected that it would reduce reactive power (0) but not real power (P) and, because only real power (P) is metered, there is no perceived requirement to implement a PFC solution for minimizing the apparent power (S) component.

Certain prior art devices are known for use with domestic circuits, such as circuit 201, which aim to reduce the real power component (P). Such a reduction is however achieved at the expense of an increase of the reactive power (Q), i.e. a worse power factor with a value further distanced from the optimum value I. Such a solution does not reduce the requirement in apparent power and, in some jurisdictions including the United Kingdom, is illegal.

There is a requirement for an improved electrical circuit, suitable for reducing both the apparent power (S) for the benefit of the production requirements of utility companies, and the real power (P) for the benefit of energy consuming households.

Summary of the Invention

According to a first aspect of the invention, an apparatus is provided for coupling to a mains supply, the mains supply having a reactive power component (Q), an apparent power component (S), a real power component (P) and a load component, the apparatus comprising mains coupling means operatively coupling the apparatus to the mains supply, and at least one capacitor (Cl), wherein the mains coupling means and the at least one capacitor are connected to one another in parallel, and wherein, in use, the apparatus reduces the real power component of the mains supply, by reducing both the reactive power and the apparent power components. * 30

The apparatus preferably further includes at least one resistor (RI) and at least one * ** voltage dependent resistor (VDR), wherein the mains coupling means, the at least one capacitor, the at least one resistor and the at least one voltage dependent resistor are **.

connected to one another in parallel and wherein, in use, the combination of the at least one capacitor, at least one resistor and at least one voltage dependent resistor reduces the real power component of the mains supply, by reducing both the reactive power and the apparent power components.

The voltage of the mains supply is preferably selected from the group comprising 110 volts, 220 volts, 240 volts or 415 volts 3-phase.

The mains coupling means is preferably selected from the group comprising a two-pin plug, a two-pin earthed plug and a three-pin earthed plug.

The capacitor is preferably manufactured as one selected from the group comprising a ceramic disc, a metalized film and a metalized paper. The film capacitor is preferably manufactured in a material selected from the group comprising at least self-healing metalized polyester, polypropylene and polyfilm. The capacitor is preferably housed in a flame retardant or flame-proof case.

The capacitance of the capacitor is preferably included in the range of 0.OOlpF to 1 OpF. The capacitance of the capacitor is more preferably included in the range of 0.01 pF to 0.O5pF. The capacitance may realised with a single capacitor, or multiple capacitors.

The capacitor is preferably a Class Xl capacitor. The capacitor may be selected from the group of classes comprising Xl, X2 and X3. Alternatively, the capacitor is a Class Yl capacitor. The capacitor may be selected from the group of classes comprising Yl, Y2, Y3andY4.

Generally, the capacitance and class of the capacitor will depend on mains voltage, frequency and required PF correction. S... * .

In an alternative embodiment of the invention, the apparatus comprises a plurality of capacitors of a same or different classes. Such a configuration may for instance be *.: 30 dictated by jurisdiction -specific safety standards, or by the reliability required by filling same into a given enclosure.

I

The resistor is preferably a beed component having a resistance value comprised in a range such as to avoid too small a resistance, in which case current would bleed, waste power and produce heat, and such as to avoid too large a resistance, in which case a large potential would remain across the capacitor, and require too long a period of time for discharging after de-coupling the apparatus from the mains. The resistance value is preferably comprised in a range of 500k to 2M Ohms. The resistance value is preferably 1M Ohm.

The voltage dependent resistor may be a varistor comprising metal oxides, having an operative voltage range dependent upon the voltage of the mains supply with which the apparatus will be used.

The voltage dependent resistor usefully suppresses transients in the apparatus, acting as a protection against surges amounting to 800 to 900 Joules.

The apparatus preferably further comprises circuit breaking means. The circuit breaking means is preferably a fuse having a rating in the range of 0.5 ampere to 13 amperes, more preferably 1 ampere. The fuse usefully limits the risk of resonance in the circuit.

In an alternative embodiment of the invention, the apparatus further comprises first illumination means. The illumination means may be provided to indicate an operating condition of the apparatus, such as an "in use" status indicator and/or alternatively indicating a fault" status. The first illumination means may be se'ected from the group comprising a LED, a gas discharge lamp, and a filament lamp or bulb. The first illumination means may usefully double as an ambient light.

The apparatus may optionally comprise first and second illumination means, for instance both a status indicator and an ambient light.

In the embodiment wherein the apparatus comprises illumination means in the form of an ambient light, a rheostat or other means may be usefully provided to further vary the light intensity of the illumination means.

*, The reduction of the real power component (P) may be in the range of I to 29%.

Preferably, the reduction of the real power component (P) is in the range of 5 to 25%.

According to a second aspect of the invention, an electricity supply system is supplied, which comprises an electricity producing facility connected to a supply network and supplying electricity thereto, the network comprising a plurality of electricity supply outlets from which to power electrical appliances connected thereto, wherein at least one electricity supply outlet is connected to an apparatus described above irrespective of the embodiment, for reducing each of the reactive, apparent and real power components of the mains power circulating in the network.

Preferably, a plurality of electricity supply outlets are connected to a corresponding plurality of apparatuses as described above irrespective of the embodiment, for further reducing the apparent and real power in the supply network.

Brief Description of the Drawings

Figure 1 illustrates a domestic environment having an electrical circuit with a number of mains supply sockets, to which a number of electrical appliances are connected; Figure 2 is a schematic representation of the electrical circuit shown in Figure 1, having a load; Figure 3 is a schematic representation of the load shown in Figure 2, including the appliances shown in Figure 1 connected to the circuit in parallel; Figure 4 is a graphical depiction of the relationship between the three components of the mains supply within the electrical circuit of Figure 1 to 3, including an apparent power component (S), a real power component (P) and reactive power component (Q); * *** Figure 5 is a graphical representation of the combination of the respective power components for each of the appliances shown in Figures 1 to 3; ** * Figure 6 is a schematic representation of a first electrical circuit according to the *** . * present invention; Figure 7 illustrates several embodiments of the circuit shown in Figure 6; I..

S

Figure 8 is a schematic representation of a second electrical circuit according to the present invention; Figure 9 illustrates several embodiments of the circuit shown in Figure 8; Figure 10 is a schematic representation of a third ejectrical circuit according to the present invention; Figure 11 illustrates an embodiment of the circuit shown in Figure 10; Figure 12 illustrates an apparatus according to the invention in use within the environment shown in Figure 1; Figure 13 is a schematic representation of the electrical circuit shown in Figure 2, is incorporating an apparatus according to the invention as shown in any of Figures 6 to 10; and Figure 14 is a graphical representation of an electricity supply system incorporating a supply network with a plurality of supply outlets to which electrical appliances and a number of apparatuses as shown in any of Figures 6 to 11 are connected.

Detailed Description of the invention

The inventors have devised a simple and economical apparatus including a circuit, for improving current properties in domestic electrical networks. It is important to note that the circuit has not been designed to provide optimum power factor correction, since circuits or devices to achieve this aim require more components, are more complex and expensive to both manufacture and maintain, and require connection into the mains supply of the load which they are to correct.

30 The circuit devised by the inventors has demonstrably achieved a surprising effect, in that when improving the power factor of typical domestic equipment, the circuit also reduces real power (P) requirements: the use of the circuit allows connected electrical appliances to operate more efficiently in terms of real power, which causes a measurable reduction in supply requirements.

Test were carried out with 15 calibrated devices during duty cycles of four hours to simulate conventional use of appliances throughout a full day, firstly without the circuit for purposes of establishing control data, then with a circuit according to the present invention connected to the mains supply. Results of the tests are presented in Table 1 hereafter.

Appliance V Hz A W PF KWH Mn ______ Electric kettle (*heating) 222.90 50 3.39 740 0.99 0.27 20 100.00 with circuit 223.00 50 3.39 740 0.98 0.26 20 96.30 Washing Machine 227.80 50 1.12 261.60 0.99 0.31 120 100.00 with circuit 227.80 50 1.10 261.90 0.95 0.27 120 87.10 LCD television 227.70 50 0.50 99.80 0.86 0.91 360 100.00 with circuit 221.70 50 0.47 100.10 0.82 0.81 360 89.02 Lighting (15x4OW bulbs) 218.30 50 4.15 551.00 0.61 3.96 360 100.00 with circuit 219.40 50 4.15 551.30 0.59 2.81 360 71.00 Tumble Dryer 226.10 50 13.20 2700.00 0.96 1.42 60 100.00 with circuit 225.40 50 13.40 2701.00 0.93 1.28 60 90.14 Dishwasher 219.80 50 0.54 114.30 0.94 1.24 120 100.00 with circuit 218.80 50 0.55 116.20 0.95 0.92 120 74.20 V -Voltage (volts) PF -Power Factor (0 to 1) Hz -Frequency (hertz) KWH -Consumption (kilowatt/hour) A -Test Current (amperes) Mn -Test Time (minutes) W -Power (watts) -Variance ECMG Worldwide Certification Solutions, Inc. -ref EMCSZO8O5I2O6SW, sample 008196, number Wt056000165

Table I

Whilst a reduction in the apparent power component (S) and in the reactive power component (Q) were expected, surprisingly, the test results have consistently indicated that the real power component (P) has also reduced. Test data confirms that the reduction in the real power component (P) can range between 1 and 29% and, in a conventional domestic environment 100 such as that simulated for the test, a reduction of 5 to 25% can be consistently expected. S... * .

This reduction will manifestly depend on the number, type and respective internal components of electrical appliances in any given domestic household, whereby results are expected to fluctuate in a broader range and a further series of tests carried out in actual sample households has indicated a range of 5% to 37.5%, with an accepted average of approximately 20%. This range compares favorably with the initial tests conducted in *:*::* laboratory conditions.

An embodiment of the circuit devised by the inventors, with which the above tests were conducted, is shown in Figure 6. The circuit 601 according to the present invention comprises mains coupling means for operatively coupling the circuit to a mains supply, in the example a live connector 602 and a neutral connector 603 for connecting to a mains socket 101. The circuit 601 further comprises at least one capacitor 604, at least one resistor 605 and one voltage dependent resistor (VDR) 606. The capacitor 604, resistor 605 and VDR 606 are connected to circuit 601 in parallel.

Capacitor 604 in the example is a Class Xl capacitor. The class X is preferred due to the expected preferred use of the present invention in a general household, since class X is for applications where failure would not lead to electric shock, and because the circuit will be expectedly be connected directly to the mains supply upstream of the equipment fuse. Class Xl capacitors are intended to operate safely even in the presence of surges of up to 4000V in the mains supply. By contrast, class X2 capacitors are intended to operate safely even in the presence of surges of up to 2500V in the mains supply. The class of capacitor may be dictated by considerations of size and cost when manufacturing a circuit according to the present invention, and the above embodiments are provided by way of non-limitative example only. Furthermore, alternative embodiments are considered, wherein a plurality of capacitors of a same or different classes are used instead, for instance to meet jurisdiction -specific safety standards.

Resistor 605 is a drain resistor having a resistance value comprised in a range such as to avoid too small a resistance, in which case current would be bled, waste power and produce heat, and such as to avoid too large a resistance, in which case a large potential would be generated across the capacitor, and require too long a period of time for discharging after de-coupling the circuit from the mains. In the example, the resistance value is 1M Ohm. S...

S..... * .

The VDR 606 is a metal oxide VDR, s, having an operative voltage range dependent *** 30 upon the mains voltage the apparatus will be used with. The voltage dependent resistor usefully suppresses transients in the circuit 601, acting as a protection against surges *:*:: amounting to 800 to 900 Joules.

The circuit also comprises a fuse having a rating of 13 amperes, which limits the risk 3 5 of resonance in the circuit.

Through a variety of tests detailed hereinbefore, the results of which are disclosed in table 1 within the present specification, the inventors have achieved a surprising and unexpected effect, in that a synergistic affect is achieved by the arrangement of the circuit 601 and its components, wherein the element of power factor correction achieved by the circuit reduces not only the reactive power component (Q) present in the domestic circuit 201 when circuit 601 is connected thereto, but also the apparent power component (S), whereby the real power component (P) is itself reduced in proportion. The tests indicate that a reduction in the real power component (P) of the order of 1 to 20% and, on average, of 13% can be achieved.

Circuit 601 may be implemented in a wide variety of apparatuses, either in a self-contained form in order to extend the benefit of the present invention to existing domestic circuits and electrical appliances connected thereto, or embedded in new domestic appliances (e.g. washing machines, televisions and the like) as a part of their internal or external mains connectivity. A variety of embodiments are shown in Figure 7 by way of example only, of a standalone apparatus for use in a domestic or office environment.

Considering the simplicity of the circuit 601, an apparatus 701 may contain circuit 601 within a sealed body 702, the shape and dimensions of which may vary to a very wide extent. The live and neutral connectors 602, 603 may be selected from the group comprising two-pins (703), two-pin earthed (704) and three-pin earthed (705), as required by the configuration of the mains socket 101 to which the apparatus should be connected.

In certain circumstances, it may be advantageous for the body 702 to feature as low a profile as the internal circuitry 601 and components 604, 605, 606 thereof allow, to render the apparatus as unobtrusive as possible and/or facilitate its location behind furniture and/or appliances, and an example apparatus 706 is shown. SI..

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I..... * .

In any case, the internal volume of the body 702, 706 is preferably sufficient to ** 30 accommodate circuit 601 and its component 604, 605, 606 and the heat dissipation requirements thereof. The apparatus is sealed to prevent ingress and tampering by users, *:::* to ensure that the apparatus does not become a potential shock or fire hazard.

*. Although varistors such as VDR 606, benefit from a potentially infinite lifetime in terms of the number of power surges they can withstand, under exceptional circumstances such as a lightning strike entering circuit 201 and circuit 601 when connected thereto, or other power surges of uncharacteristically high potential, it is possible for the capacitor 604, resistor 605 or varistor 606 to fail.

With reference to Figure 8, an alternative embodiment 801 of circuit 601 includes first illumination means 802, implemented in circuit 601 such that failure of any of circuit components 604, 605 or 606 will interrupt power supply thereto and therefore interrupt the illumination provided by the illumination means 802. The illumination means 802 therefore acts as an indicator of the functional status of circuit 801 within apparatus 702 and, with reference to Figure 9, may be embodied as a light emitting diode (LED) 901 observable through, or protruding from, an aperture 902 in the body 702 of the apparatus.

However, the first illumination means 802 may fulfill an alternative and additional function when embodied as a low-powered, low-intensity safety light, commonly referred to as a "night light", an example of which is shown in Figure 9 as 903. Further to providing an indication of the operational status of circuit 801, the safety light 903 further contributes to power saving within a domestic environment by reducing or removing the need to switch on lighting appliances such as filament lamp 103 when a user moves within the environment 100 in darkness. The safety light 903 may still be implemented as a LED, and in this embodiment the aperture within body 702, 706 has a substantially larger aperture 904, relative to the LED -sized aperture required for indicator 901. The aperture area 904 is preferably covered with a light-diffusing membrane, suitable for converting the relatively high-intensity light emitted by the LED into a softer, low-intensity light suitable for illuminating only the immediate periphery of apparatus 702.

Users of apparatus 702 equipped with a safety light 903 may have a requirement to further vary the intensity of the emitted light, for instance by reason of vision impairment, or : a temporary requirement for brighter illumination of the area immediately surrounding the * * unit 702. Accordingly, a further embodiment 1001 of circuit 601 including the first ** I : 30 illumination means 802 also includes illumination adjusting means 1002. Those skilled in ** the art will appreciate that any mechanical or electronic means suitable for varying the illumination may be used, which are well known in the art, and an example of such a mechanism is shown in Figures 10 and 11 by way of non-limitative example only, as a a variable resistor, or rheostat, 1101.

The domestic environment 100 of Figure 1 is again shown in Figure 10, wherein the circuit 601 contained in a sealed unit 702 is shown in use, connected by its mains coupling means 705 to the household mains supply through a mains power socket 101.

The load 204 within an environment 100 is present in the circuit 201 at any one time, whereby the power flowing through circuit 601 exhibits the combined real power component (P), apparent power component (S) and reactive power component (0) described in relation to Figure 5. In addition to passing through capacitor 604 and resistor 605, power passing through varistor 606 is clipped, in that surges and noise inherent to the flow are reduced, for instance those caused by highly inductive or capacitive loads including the electrical motors respectively in washing machine 107 and tumble dryer 108, and the compressor in fridge freezer 106.

In use, the circuit 601 implemented in an apparatus 702 is interfaced with the electrical circuit 201 first shown in Figure 2, by coupling the mains coupling means 705 with a mains supply socket 101. With reference to Figure 13, a new electrical circuit 1301 is provided in domestic environment 100, having a power factor correction capacity, the effect of which scales in dependence with the number of appliances 102 to 108 connected to circuit 1301 and contributing to its load 204 at any one time. A switch 1302 is shown, which corresponds to the on/off switch optionally equipping the mains supply socket 101 to which the apparatus 702 is connected, for selectively enabling or disabling circuit 601 therein.

An electricity supply system is shown in Figure 14, which incorporates an electricity supply network 1401 connecting an electricity producing facility (not shown) to a plurality of domestic dwellings. Each such dwelling corresponds substantially to the example domestic environment 100 of Figure 1. Whilst a circuit 601 according to the invention ***.

usefully reduces the three components of the power circulating in electrical circuit 1301, * S the reduction performed at a single dwelling is trivial, relative to the scale of supply network ** S : 30 1401 and the combined loads of each dwelling connected thereto. Since the implementation of circuit 601 in a standalone sealed unit 702 allows the retrofitting of any conventional domestic circuit 201 into the optimized, power factor-corrected domestic *:*::* circuit 1301, the connection of a number of circuits 601 with respective domestic circuits 201 over time may result in a mix of domestic dwellings 1402 connected to the supply network 1401 and retaining a conventional electrical circuit 201, and a number of dwellings 1403 having an electricity circuit 1301, the aggregated power factor correction capacity of which may in turn reduce the requirement in apparent power to be output by the electricity producing facility.

Several embodiments of a stand alone, sealed apparatus 702 enclosing the circuit 601 have been described herein by way of example only, and it will be understood by persons skilled in the art that circuit 601 may be embodied in a very wide variety of other form factors. For instance, domestic appliances known to contribute a substantial amount of reactive power component (Q), such as fridge freezer 106 or washing machine 107, may be manufactured in such a way as to incorporate circuit 601 within their circuitry, in order to remove the requirement for consumers to purchase a stand alone unit 702. Circuit 601 may likewise be implemented in existing power-controlling devices, for instance as part of the circuitry of a general main switch 203, or fuse box connected thereto. S... * . *S**

*** I.. * * * . * * *. * S.. * S. * . . * S.

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Claims

Claims 1. Apparatus for coupling to a mains supply, comprising: mains coupling means operatively coupling the apparatus to the mains supply, the mains supply having a reactive power component (Q), an apparent power component (S), a real power component (P) and a load component; and at least one capacitor (Cl); wherein the mains coupling means is connected to the at least one capacitor (Cl) in parallel, and wherein, in use, the apparatus reduces the real power component of the mains supply, by reducing both the reactive power and the apparent power components.
2. Apparatus according to claim 1, further comprising: at least one resistor (Ri); and at least one voltage dependent resistor (VDR); wherein the mains coupling means, the at least one capacitor, the at least one resistor and the at least one VDR are connected to one another in parallel and wherein, in use, the combination of the at least one capacitor, at least one resistor and at least one voltage dependent resistor reduces the real power component of the mains supply, by reducing both the reactive power and the apparent power components. * * ** *

: 30
3. Apparatus according to claim 1 or 2, wherein the voltage of the mains supply is selected from the group comprising 110 volts, 220 volts, 240 volts or 415 volts tn-phase. * S. * S * *. * 0**
4. Apparatus according to any preceding claim, wherein the mains coupling means is selected from the group comprising a two-pin plug, a two-pin earthed plug and a three-pin earthed plug.
5. Apparatus according to any preceding claim, wherein the capacitor is manufactured as one selected from the group comprising a ceramic disc, a metalized film and metalized paper.
6. Apparatus according to claim 5, wherein the capacitor is manufactured in a material selected from the group comprising at least self-healing metalized polyester, polypropylene and polyflim.
7. Apparatus according to any preceding claim, wherein the capacitor is housed in a flame retardant or flame-proof case.
8. Apparatus according to any preceding claim, wherein the pF capacitance of the capacitor is in the range of 0.001 pF to lOpF.
9. Apparatus according to claim 8, wherein the capacitance of the capacitor is included in the range of 0.01 pF to 0.O5pF.
10. Apparatus according to any preceding claim, wherein the capacitor is selected from the group of classes comprising Xl, Xl, X2 and X3.
11. Apparatus according to claim 10, wherein the capacitor is a class Xl capacitor. S S...

:
12. Apparatus according to any of claims 1 to 10, wherein the capacitor is * . selected from the group of classes comprising Yl, Y2, Y3 and Y4.

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13. Apparatus according to any preceding claim, further comprising a plurality of capacitors, of a same or different classes. * S. a-* * ._
14. Apparatus according to any of claims 2 to 13, wherein the resistor is a bleed component to prevent electrical shock from the cap.
15. Apparatus according to claim 14, wherein the resistance value is 1M Ohm.
16. Apparatus according to any of claims 2 to 15, further comprising a plurality of resistors.
17. Apparatus according to claim 2 or any of claims 3 to 16 when depending on claim 2, wherein the varistor comprises metal oxides.
18. Apparatus according to claim 2 or any of claims 3 to 17 when depending on claim 2, wherein the voltage dependent resistor is apt to suppress transients and protect the apparatus against surges amounting to 800 to 900 Joules.
19. Apparatus according to any preceding claim, further comprising circuit breaking means.
20. Apparatus according to claim 19, wherein the circuit breaking means is a fuse having a rating in the range of 3 amperes to 32 amperes
21. Apparatus according to claim 20, wherein the fuse has a rating of 13 amperes.
22. Apparatus according to any preceding claim, further comprising at least one illumination means.
23. Apparatus according to claim 22, wherein the at least first illumination means indicates an operating condition of the apparatus. * * ***.
24. Apparatus according to claim 22 or 23, wherein the at least first illumination ***.** * means provides a low -intensity light. ** * * S S * S.*: *
25. Apparatus according to any one of claims 22 to 24, wherein the at least first illumination means is selected from the group comprising a LED, a gas discharge lamp and a filament lamp or bulb. S..
26. Apparatus according to any of claims 22 to 25, further comprising second illumination means.
27. Apparatus according to any of claims 22 to 26, further comprising means to vary the intensity of the illumination provided by the illumination means.
28. Apparatus according to any preceding claim, wherein the reduction of the real power component (F) is in the range of 1 to 29%.
29. Apparatus according to claim 28, wherein the reduction of the real power component (P) is in the range of 5 to 25%.
30. Electricity supply system, comprising: an electricity producing facility connected to a supply network and supplying electricity thereto, the network comprising a plurality of electricity supply outlets from which to power electrical appliances connected thereto; wherein at least one electricity supply outlet is connected to an apparatus according to any of claims 1 to 29, for reducing each of the reactive, apparent and real power components in the mains power circulating in the network.
31. Electricity supply system according to claim 30, further comprising a plurality of electricity supply outlets connected to a corresponding plurality of apparatuses according to any of claims 1 to 29. * * *S.S * S *S * * * * * S. S.. * .* * S S * .. * S..S