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    • 专利摘要:
    The invention describes a method of realizing an effective integral compensator of imbalances for loads fed by a balanced three-phase source, minimizing the compensator imbalances caused by energy losses in elements of said compensator. The method comprises the steps of a) calculating the complex susceptances of the elements of an ideal integral compensator; b) since a real integral compensator resembles the parallel connection of the ideal integral compensator of step a) and additional loads, calculate the complex susceptances of an additional loss compensator; c) obtain at least one of the loss conductance (Gk) and the energy losses (Pk) for each element (k) of the compensator; and d) determine the susceptances of elements of the effective integral compensator, which compensates the imbalances and the reactive energy of the load, as well as the imbalances caused by the energy losses in the elements of the compensator itself. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2702530A1
    申请号:ES201830563
    申请日:2018-06-08
    公开日:2019-03-01
    发明作者:Martinez Vicente Leon；Romeu Joaquín Montanana
    申请人:Universidad Politecnica de Valencia；
    IPC主号:
    专利说明:

    [0001] PROCEDURE FOR THE REALIZATION OF AN INTEGRAL COMPENSATOR AND
    [0002]
    [0003] Field of the invention
    [0004] The present invention relates generally to the field of passive devices in charge of reducing the impact that single-phase and three-phase loads can exert on the electrical network. More specifically, the invention relates to the field of passive integral compensators of reactive power and imbalances, for loads and electrical installations powered by three-phase sources.
    [0005]
    [0006] BACKGROUND OF THE INVENTION
    [0007] In the art, passive compensators dedicated to reducing the impact that can be exerted by single-phase and three-phase loads, very intensive, on the electric network or any other three-phase source, such as battery charging systems of electric cars and lighting receivers, are already known. among others.
    [0008] The intensive loads are those, single-phase or three-phase, high power, which absorb high-value currents. Therefore, its connection to the electricity grid can cause significant energy losses and high voltage drops, which affect the proper functioning of the receivers and electrical installations, both their own and that of other users. Within this type of loads are the electric vehicle charging systems and the lighting receivers, among others. Electric vehicle charging systems require the use of single-phase, 230 V, or three-phase, 400 V power supplies, with powers between 3.3 and 43 kW, depending on the charging time. The slower charging systems are less intensive, with 16 A currents, while the very fast charging systems (20-30 minutes) are very intensive, with currents of up to 63 A, in alternating current, and up to 125 A, in direct current, obtained by rectification of alternating current. Among the lighting receivers, the LED projectors are particularly intensive, for outdoor sports events, with powers of 1750 W, at 230 V, and the halide projectors, with powers of 2000 W, at 400 V.
    [0009] In addition to the aforementioned technical drawbacks which give rise to these charges, caused by the circulation of high value streams, other economic effects must be added, such as the increase in the costs of the electrical installations where said loads, derived from the greater value of the nominal powers of the necessary transformers and the increase of the sections of the conductors of the electric lines.
    [0010] All these adverse effects can be alleviated by the use of passive integral compensators, which are mainly composed of coils and capacitors.
    [0011] The main mission of these compensators is to reduce the value of the unbalance currents supplied by the three-phase power network, transforming unbalanced single-phase and three-phase loads into balanced three-phase receivers. Additionally, the compensators can also supply the reactive currents, necessary for said loads.
    [0012] In industrial practice, certain electronic converters, known as active filters, are known, of which there is a great variety in terms of constitution and manufacturing companies, and which can perform the functions indicated above. These devices can "manufacture", with great precision, reactive and unbalance currents that require fixed and variable loads. But nevertheless, they present important drawbacks that make them little useful for their application to electric vehicle charging systems and to lighting receivers, namely: they are expensive, bulky and their coils usually have significant energy consumption.
    [0013] Passive integral compensators, on the other hand, are much cheaper devices, since they do not have elements of the power electronics nor do they need control circuitry, and their constitution is relatively simple for fixed loads, since they are formed by coils and fixed value capacitors, only, and occupy much less space than active filters of the same power.
    [0014] Patents ES2156828B1, ES2169651B1 and ES2333838B2, presented by the present inventors, describe three passive integral compensators. The first two are for fixed, single-phase and three-phase loads, three and four wires, respectively, whose elements are coils and capacitors, which can be calculated based on the equations collected both in the documents of these patents and in the publication "Conductive circuits linear ", by Vicente León Martínez, Joaquín Montañana Romeu and Antonio Cazorla Navarro, Editorial Universitat Politécnica de Valencia, 2018, ISBN 978-84-9048 608-5. The compensator developed in the third patent is for variable single-phase and three-phase loads; its constitution and formulation are described in the article "Unbalance Compensator for Three-Phase Industrial Installations", León-Martinez, V .; Montanana-Romeu, J., et al, Latin America Transactions, IEEE, vol. 9, no. 5, p.
    [0015] 808-814, September 2011, DOI: 10.1109 / TLA.2011.6030993, and in the paper "Passive unbalance compensation device for three-phase variable loads", by León-Martinez, V .; Montanana-Romeu, J .; et al; presented at the 10th International Conference on Environment and Electrical Engineering (EEEIC), 2011, p.
    [0016]
    [0017] Other relevant references on these compensators include: 1) Jeon, S.J. and Willems, J.L. in the article "Reactive power compensation in a multi-line system under sinusoidal unbalanced conditions", International Journal of Circuit Theory and Applications, April 2010, Wiley, DOI: 10.1002 / cta.629, and 2) F.R. Quintela, J.M.G. Arévalo, R.C. Redondo and N.R. Melchor in the article "Four-wire three-phase load balancing with static var compensators", Electrical Power and Energy Systems no. 33, Elsevier Journal, p. 562-568, January 31, 2011.
    [0018] However, in practice, the compensators with passive elements, mentioned in the above bibliographic references, can not compensate for the imbalances caused by the energy losses in the elements of the compensator itself, which are determined by the quality factor of the reactances of the compensator (fundamentally, of the quality or energy lost by its coils, since the losses in the real capacitors are usually negligible). If the coils are of excellent quality (with quality factors QF greater than 100), the compensators described in patents ES2156828B1 and ES2169651B1 work correctly, balancing the currents and reducing their value up to 0.333 times the current without compensator, in the compensators of single-phase loads in star (ES2169651B1), and up to 0.577 times, in the compensators of monophasic triangle loads (ES2156828B1). However, coils with such high quality factors are expensive, heavy and bulky; and the use of lower quality coils, cheaper and less bulky, is not advisable in these compensators, because it significantly reduces their efficiency and good performance.
    [0019] The quality factor, that is to say, the energy losses, of the elements of the real integral compensators therefore harms the proper functioning thereof, by introducing additional imbalances on the line currents.
    [0020] Therefore, there is a need in the art for a method of designing and implementing integral compensators that compensates for the malfunctions caused by the energy losses in the compensator itself, so that good results are obtained even with economic coils with quality factors. acceptable
    [0021]
    [0022] Summary of the invention
    [0023] To solve the problems of the prior art, the present invention discloses a method of realizing an effective integral compensator of imbalances for loads fed by a balanced three-phase source, minimizing the compensator imbalances caused by energy losses in elements of said compensator, comprising The procedure stages:
    [0024] a) calculate the complex susceptances of the elements of an ideal integral compensator;
    [0025] b) since a real integral compensator resembles the parallel connection of the ideal integral compensator of step a) and additional loads, calculate the complex susceptances of an additional loss compensator;
    [0026] c) obtain at least one of the loss conductance (Gk) and the energy losses (Pk) for each element (k) of the compensator; Y
    [0027] d) determine the susceptances of elements of the effective integral compensator, which compensates the imbalances and the reactive energy of the load, as well as as the imbalances caused by the energy losses in the elements of the compensator itself.
    [0028]
    [0029] BRIEF DESCRIPTION OF THE DRAWINGS
    [0030] The present invention will be better understood with reference to the following drawings which illustrate preferred embodiments of the present invention, provided by way of example, and which are not to be construed as limiting the invention in any way:
    [0031] Figure 1 schematically represents an integral, passive, ideal compensator connected to a three-phase load fed between phases of a three-phase source.
    [0032] Figure 2 represents the effect of the energy losses of the elements of the integral, passive, real compensator, for loads fed between phases of a three-phase source.
    [0033] Figure 3 represents the passive device, necessary to minimize the effects of the losses of the elements of the real integral compensator.
    [0034] Figure 4 represents the effective integral compensator for interphase-fed loads of a three-phase source, according to a preferred embodiment of the present invention. The effective integral compensator results from integrating in a single device the real integral compensator, shown in figure 2, with the loss compensator, shown in figure 3.
    [0035] Figure 5 schematically represents an integral, passive, ideal compensator connected to a three-phase load fed between phase and neutral of a three-phase source.
    [0036] Figure 6 represents the effect of the energetic losses of the elements of the integral, passive, real compensator, for loads fed between phase and neutral of a three-phase source.
    [0037] Figure 7 represents the passive device, necessary to minimize the effects of the losses of the elements of the real integral compensator.
    [0038] Figure 8 represents the effective integral compensator for loads fed between phase and neutral of a three-phase source according to a second preferred embodiment of the present invention. The effective integral compensator results from integrating in a single device the real integral compensator, shown in Figure 6, with the loss compensator, shown in Figure 7.
    [0039] Figure 9 shows the passive elements that integrate the effective integral compensator according to a preferred embodiment of the present invention for loads fed between phases of the three-phase source, as well as the hardware for the measurement and visualization of data.
    [0040] Figure 10 shows the passive elements that integrate the effective integral compensator according to another preferred embodiment of the present invention for loads fed between phase and neutral of the three-phase source, as well as the device for the measurement and visualization of data.
    [0041] Figure 11 shows the method of measuring the loss reduction factor (FRP) and the monitoring coefficient of good functioning (£) of the effective integral compensator according to a preferred embodiment of the present invention.
    [0042]
    [0043] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the preferred embodiment of the present invention, there is disclosed a method of realizing an effective integral compensator of imbalances for loads supplied by a balanced three-phase source, minimizing the compensator imbalances caused by energy losses in elements of said compensator. In particular, the procedure is used to determine the characteristics of the elements of integral passive imbalance compensators for single-phase and three-phase loads, with three and four wires, fed by the electrical network or any other balanced three-phase source, bringing the power factor of electrical installations closer to the unit. In a novel way, the compensators obtained by the method according to the present invention minimize the undesirable effects caused by the poor quality (energy losses) of the reactors (coils and capacitors) of the compensator.
    [0044] The method according to the preferred embodiment comprises the steps of:
    [0045] a) calculate the complex susceptances of the elements of an ideal integral compensator;
    [0046] b) since a real integral compensator resembles the parallel connection of the ideal integral compensator of step a) and additional loads, calculate the complex susceptances of an additional loss compensator;
    [0047] c) obtain at least one of the loss conductance (Gk) and the energy losses (Pk) for each element (k) of the compensator; Y
    [0048] d) determine the susceptances of elements of the effective integral compensator, which compensates the imbalances and the reactive energy of the load, as well as the imbalances caused by the energy losses in the elements of the compensator itself. According to another preferred embodiment of the present invention, the method further comprises the steps of: e) calculating the loss reduction factor (FRP%) as the quotient between the losses caused by the operation of the unbalanced load in the different elements of the system with and without compensator integral; Y
    [0049] f) verify the correct functioning of the integral compensator from the verification coefficient s between the value of the FRP% calculated with optimal values of the currents and with measured real values thereof;
    [0050] determining that the operation of the integral compensator is better the closer the value of s approaches 1.
    [0051] From the point of view of the formulation of the elements that make up the compensator, two practical cases are distinguished: 1) single-phase and three-phase loads fed between phases of a three-phase source (in delta), and 2) single-phase and three-phase loads fed between phases and neutral of a three-phase source (star). Next, the equations to be applied in each of said practical cases for the implementation of the a) to f) above described steps of the method according to the preferred embodiment of the present invention will be detailed.
    [0052]
    [0053] 1) Charges fed between phases of a three-phase source (in delta).
    [0054] The ideal integral compensator for single-phase and three-phase loads of complex admittances YX = GX BX in each phase (x = 12,23,31), which are fed between phases (z = 1,2,3) of a balanced three-phase source, in star, is formed by a single connection in delta, of ideal coils and capacitors, arranged as shown in connection (2) of figure 1. The complex susceptances ( Bil2, Bil23, Bll31) thereof are calculated by any of the equations [1] and [2] below:
    [0055]
    [0056]
    [0057]
    [0058] where Yx - Gx B x are the complex admittances in each phase (x - 12,23,31) of the load; (PX, QX ) are the active and reactive powers consumed by each phase (x = 12.23,31) of the load; Line is the effective value of the line voltage (between phases), j - 1z90 ° is the imaginary unit, in the Gaussian plane; and the asterisk (*) denotes the conjugate of a complex number.
    [0059] The reactance connections, with the values determined by equations [1] or [2], supply the unbalance currents, in reverse sequence, in this case, as well as the direct sequence reactive currents, which absorb the loads.
    [0060] The values calculated on the basis of equations [1] and [2] are ideal and do not take into account the practical effects of the real reactances. These effects are observed graphically in the connection (4) of figure 2, separately from the ideal compensator, by means of three additional conductances ( G i l2, G i23, G i31 ) connected in a triangle, representing the energy losses existing in the reactors real. The real integral compensator is then equivalent to the association (3), formed by the parallel connection of (2) and (4), in figure 2.
    [0061] The additional conductances (G ix, x - 12,23,31) determine additional consumption of active power ( P ix = G ix • V line , x = 12,23,31), which give rise to additional imbalances of
    [0062] active power and who are ultimately responsible for the evil
    [0063] operation of the real integral compensator. The compensation
    [0064] of these additional imbalances and, therefore, the
    [0065] minimization of the effects of the energy losses of the
    [0066] integral integral compensator (3), can be carried out under the
    [0067] Consideration that G x (4) conductances constitute another
    [0068] unbalanced load, connected in parallel with the actual load
    [0069] (1), of admittances in each phase Yx = Gx B xf and that, therefore,
    [0070] the additional imbalances that this burden produces can
    [0071] compensate by connecting an additional compensator
    [0072] (5), in figure 3, whose susceptances (B'x, x = 12,23,31) can
    [0073] obtained by any one of equations [3] and [4]
    [0074] then analogous to equations [1] and [2]:
    [0075]
    [0076]
    [0077] in which G il2, G i23, G i31 are the conductances and P¿12, ^ 23, ^ 31
    [0078] are the energy losses of the compensator charges
    [0079] real integral.
    [0080] In order that these latter ballasts do not introduce
    [0081] new losses, this compensator (5) must be integrated into the
    [0082] Integral compensator of the real load (3), forming a single
    [0083] device, as shown in Figure 4. The values
    [0084] ( B f 12, B f 23, B f 31 ) of the susceptances (7) of this compensator Effective integral (6) are obtained, based on the conductances and susceptances of the phases of the load (1) and of the conductances of the losses in the real integral compensator (3), by means of any of the equations [5] and [6] below:
    [0085]
    [0086]
    [0087] The inductive or capacitive character of the elements of each phase of the effective integral compensator (6) does not change with respect to that of the elements of the real integral compensator (3), because the susceptances ( B'i l 2, B 'i23, B 'i31 ) are, in practice, always smaller than the susceptances ( B 12, B 23, B 31 ). Consequently, the energy losses (4) of the effective integral compensator (6) are practically equal to those of the real integral compensator (3).
    [0088] The line currents supplied by the three-phase source are, in each phase ( z - 1,2,3) thereof, the following:
    [0089] - Without compensator. Equal to those absorbed by the load,
    [0090]
    [0091]
    [0092] being ¡adz and Irdz the respective complex currents active and reactive, of direct sequence, and / z the complex current of imbalance (of inverse sequence), resulting from applying the Fortescue theorem.
    [0093] - With ideal integral compensator (figure 1). Equal to the direct sequence active currents ( Ta dz ), whose effective value is, depending on the total active power consumed by the load ( P = P 12 + P23 + P 31 ) and the effective value of the line voltages ( Vi ín ea ):
    [0094]
    [0095]
    [0096] - With real integral compensator (figure 2). Equal to the complex sum of the active currents of direct sequence of the load ( Ta dz ) and of the active currents of losses (/ j, z):
    [0097]
    [0098]
    [0099] in which I ^ dz and I ^ z are the respective direct currents of direct sequence and unbalance, of each phase (z = 1,2,3), resulting from applying the Fortescue theorem to the loss currents (/ j , z). The effective value of I'adz is, as a function of the total energy losses in the real compensator ( Pp = P il2 + Pi23 + P¿3i) and the effective value of the line voltages (^ l line ):
    [0100]
    [0101] - With effective integral compensator (figure 4). Equal to the complex sum of the direct currents of the direct sequence of the load ( Ta dz ) and losses (/ ¿dz):
    [0102]
    [0103]
    [0104] being its effective value in each phase (z = 1,2,3) of the line:
    [0105]
    [0106]
    [0107] These currents are balanced, direct sequence, have no reactive component and are smaller than the currents (/ z) supplied with real integral compensator according to the equation [9], since they do not contain the unbalance currents caused by the losses in the own compensator (/ z).
    [0108] To determine the impact produced by the connection of the integral compensator for loads fed between phases of a three-phase source, the loss reduction factor (FRP%) is established as the ratio between the losses caused by the operation of the unbalanced three-phase load in the different elements of the system (generators, transformers and lines) with and without integral compensator, and is expressed as a hundred, depending on the line currents, according to equation [13] below:
    [0109]
    [0110]
    [0111] in which 1% are the effective values measured in each phase (z = 1,2,3) of the lines with the integral compensator connected in terminals of the load e lz are the effective values of the line currents absorbed by the load without the compensator.
    [0112] The proper functioning of the integral compensator and its adaptation to the theoretical forecasts is obtained by the surveillance quotient (£ ) by means of equation [14] below, between the value of the FRP % calculated on the basis of equation [13], with the optimal values of 1 % currents, defined by equation [12], and with practical values, measured, of said currents:
    [0113]
    [0114]
    [0115] The optimum operation for each integral compensator corresponds to the value £ = 1. Lower values of this parameter imply worse operation of the compensator.
    [0116]
    [0117] 2) Charges fed between phase and neutral of a three-phase source (star).
    [0118] The integral compensator for single-phase and three-phase loads, complex admittances YZ = GZ + BZ fed between the phases (z = 1,2,3) and the neutral of a balanced three-phase source is formed by a star connection (with neutral conductor) and another one in triangle, of ideal coils and capacitors, arranged as shown, in a general way, in (9) of figure 5, and whose complex susceptances are ( B¡kl, B¡k2, B¡k3), for the connection in star, and ( B lil, Bli2, Bli3), for the connection in a triangle. These complex susceptances are calculated by any one of equations [15] and [16] below:
    [0119]
    [0120]
    [0121] where YZ = GZ BZ are the complex admittances in each phase ( z = 1,2,3) of the load; ( PZ, QZ ) are the active and reactive powers consumed by each phase (z = 1,2,3) of the load; Vfase is the effective value of the voltage between phase and neutral (simple); j = 1z90 ° is the imaginary unit, in the Gaussian plane; and the asterisk (*) denotes the conjugate of a complex number.
    [0122] The star connection, of susceptances determined by equations [15] or [16], basically supplies the reactive currents of direct sequence and of homopolar sequence, while the connection in delta provides the inverse sequence currents, which the unbalanced load needs .
    [0123] Since the real reactances have active power consumption (energy losses), the real integral compensators for star loads (figure 6), with neutral conductor (10), can be considered formed by the parallel association of the ideal compensator (9), of susceptances defined by equations [15] or [16], and two unbalanced conductance connections (11), one in star ( Gh l, G h2, G h3 ) and another in triangle ( G il, G i2, G i3 ), which represent the effects of said energy losses. These conductances suppose, in practice, additional loads, which give rise to disequilibria of active power, caused by the compensator itself, which are ultimately responsible for the malfunctioning of the passive integral compensators.
    [0124] The imbalances caused by the conductances ( Gh l, G h2, G h 3 ) can be compensated, as in the three-phase resistive loads in star, by means of two connections of coils and capacitors, one in star and another in triangle, of susceptances ( B'h l, B 'h2, B' h 3 ) and ( B'i l, B 'i2, B' i 3 ), respectively, as shown in (13) of Figure 7. The values of these susceptances are obtained by any one of equations [17] and [18] below:
    [0125]
    [0126]
    [0127] where Gh l, G h2, G h3 are the conductances and P hi, P i i 2 , P h 3 are the energy losses of the loads of the real integral compensator.
    [0128] The imbalances caused by the conductances (G il, G i2, G i 3) can be compensated in the same way as three-phase resistive triangle loads, by means of a connection, also in a triangle, as shown in (14) of Figure 7, and whose Susceptances are obtained by any of the following equations [19] and [20]:
    [0129]
    [0130]
    [0131]
    [0132] In order that the elements of the energy loss compensator, (12) in Figure 7, whose susceptances are defined by equations [17], [18], [19] and [20], do not introduce additional losses, this The compensator must be integrated, forming a single device, with the real integral compensator (10). The effective integral compensator,
    [0133] resulting from the integration of (12) into (10), is represented in (15), of Figure 8, and is formed (16) by a star connection, with neutral conductor, of susceptances ( Bj [1, Blfl2, Blfl3), and a triangle connection, of susceptances (B ^ b ^ b ^).
    [0134] The values of the susceptances of the star connection of the effective integral compensator (15), of Figure 8, are determined by any one of equations [21] and [22] below, as a function of the conductances ( G1, G 2, G 3 ) and complex susceptances ( B 1, B 2, B 3 ) of the load and of the loss conductances ( Gh l, G h2, G h 3 ) of the elements of the star connection of the real integral compensator :
    [0135]
    [0136]
    [0137] [22] The values of the susceptances of the delta connection of the effective integral compensator (15), of figure 8, are obtained, as a function of the conductances ( G1, G2, G3 ) of the load and of the conductances of losses (Gjll , Gh2 , Gh3) and ( G il, G i2, G i 3 ) of the elements of the real integral compensator, by means of any one of equations [23] and [24] below:
    [0138]
    [0139]
    [0140] The inductive or capacitive character of the elements of each phase of the effective integral compensator (15) does not change with respect to that of the elements of the real integral compensator (10), because the susceptances ( B'i l, B 'i2, B 'i3) and(Bil2,Bi23, Bi3 ) are, in practice, always lower than (B li l, li2 B, B li 3). Accordingly, the energy losses (11) of the effective integral compensator (15) are practically equal to those of the real integral compensator (10).
    [0141] The line currents supplied by the three-phase source are, in each phase ( z - 1,2,3) thereof, the following:
    [0142] - Without compensator. Equal to those absorbed by the load, / z = /. / i rd z + 'light
    [0143] [25] being ¡adz and Irdz the respective active and reactive complex currents, of direct sequence, and / z the complex current of imbalance (of inverse and homopolar sequences), resulting from applying the Fortescue theorem.
    [0144] - With ideal integral compensator (figure 5). Equal to the direct sequence active currents ( Ta dz ), whose effective value is, based on the total active power consumed by the load (P = P1 + P3 + P3 ) and the effective value of the phase voltages (Vphase ):
    [0145] r P
    [0146] Iadz ot / 3 Vfase
    [0147] [26] - With real integral compensator (figure 6). Equal to the complex sum of the active currents of direct sequence of the load ( Ta dz ) and of the active currents of losses (/ j, z):
    [0148]
    [0149] /; = /. adz Ipz ^ adz Iadz ~ I lu 'z
    [0150] [27] where I ^ dz and I ^ z are the respective direct currents of direct sequence and unbalance, of each phase (z = 1,2,3), resulting from applying the Fortescue theorem to the loss currents ( / j, z). The effective value of I'adz is, based on the total energy losses in the real compensator (P p) and the effective value of the phase voltages (Vf ase):
    [0151] Pv
    [0152]
    [0153] l adz _ or _ j _ / AND__
    [0154] 3 "fa
    [0155] [28] - With effective integral compensator (figure 8). Equal to the complex sum of the active currents of Direct sequence of charge (/ adz) and loss (/ ¿dz):
    [0156]
    [0157]
    [0158] being its effective value in each phase (z = 1,2,3) of the line:
    [0159]
    [0160]
    [0161] These currents are balanced, direct sequence, have no reactive component and are smaller than the currents (/ z) supplied with real integral compensator according to the equation [25], since they do not contain the unbalance currents caused by the losses in the own compensator (/ z).
    [0162] The impact of the integral compensator for loads fed between phase and neutral of a three-phase source is determined by the loss reduction factor (FRP%), established analogously to the load compensators fed between phases of the three-phase source, such as the ratio between the losses that the operation of unbalanced three-phase load produces in the different elements of the system (generators, transformers and lines), with and without integral compensator, and is expressed as a hundred, depending on the line currents, according to Equation [31] below:
    [0163]
    [0164]
    [0165] in which 1% and are, respectively, the effective values measured in each phase (z = 1,2,3) of the lines and of the neutral conductor (N), with the effective integral compensator connected in terminals of the load, and lz and lN are the effective values of the line currents absorbed by the load and circulating through the neutral conductor, respectively, without the compensator.
    [0166] The proper functioning of the integral compensator and its adaptation to the theoretical forecasts is obtained by the surveillance quotient (£ ) by means of equation [32] below, between the value of the FRP% calculated on the basis of equation [31], with the optimal values of 1 % currents, defined by equation [30], and with the practical, measured values of these currents, namely:
    [0167]
    [0168]
    [0169] The optimum operation for each integral compensator corresponds to the value £ = 1. Lower values of this parameter indicate worse operation of the compensator.
    [0170] The loss conductance (Gk) and the energy losses (Pk) obtained in step c) of the process according to the preferred embodiment of the present invention are calculated by equation [33] below:
    [0171]
    [0172]
    [0173]
    [0174] when the element (k) of the effective integral compensator is a coil;
    [0175] and by means of equation [34] below:
    [0176]
    [0177]
    [0178]
    [0179] when the element (k) of the effective integral compensator is a capacitor.
    [0180] In equations [33] and [34], (QFk) is the quality factor (chosen by the user or provided by the manufacturer), (tga k) is the tangent of the loss angle, B k and Vk are the values of the susceptance and the tension applied to the element k, respectively.
    [0181] Figure 9 shows a preferred embodiment of the integral integral compensator for loads fed between phases of a three-phase source, as well as its connection to said loads and to the source. The elements of said compensator (E) are associated in delta and, in turn, connected in parallel with the phases of the load. The method for determining said elements comprises the following steps:
    [0182] - From the conductances and susceptances of the phases of the load, calculate the susceptances of the elements of the ideal integral compensator for loads fed between phases of the three-phase source, applying equations [1] or [2] previously defined.
    [0183] - From the factor of quality of the coils and the tangent of the angle of losses of the capacitors, chosen by the user or provided by the manufacturer, obtain their conductance of losses by applying equation [33], or the energy losses of each one of them applying equation [34].
    [0184] - From the values of the conductances or energy losses, obtained in the previous step, determine the susceptances of the elements of the effective integral compensator, applying equations [5] or [6].
    [0185] Figure 10 shows a preferred embodiment of the integral integral compensator for loads fed between phase and neutral of a three-phase source, as well as its connection to said loads and to the source. The elements of said compensator (F) are formed by a delta connection and a star connection, with a neutral conductor, which are connected, in turn, to terminals of the load. The method for determining said elements comprises the following steps:
    [0186] - From the conductances and susceptances of the phases of the load, calculate the susceptances of the elements of the ideal integral compensator for loads fed between phases of the three-phase source, applying equations [15] or [16] previously defined.
    [0187] - From the factor of quality of the coils and the tangent of the angle of losses of the capacitors, chosen by the user or provided by the manufacturer, obtain their conductance of losses by applying equation [33], or the energy losses of each one of them applying equation [34].
    [0188] - From the values of the conductances or energy losses, obtained in the previous step, determine the susceptances of the elements of the effective integral compensator, applying equations [21] and [23] or [22] and [24] .
    [0189] Figure 11 shows a possible embodiment of the method of realization of an effective integral compensator, object of the present invention, which can be applied indistinctly both for load compensators fed between phases, and for load compensators fed between phase and neutral of the three-phase source . The procedure comprises the following steps:
    [0190] - Digital processing (17) of the sampled signals obtained by the physical system (see figure 11) for measuring and acquiring electrical signals from the device, obtaining the matrices of effective values and initial phases of the line currents supplied by the three-phase source and absorbed by the load, at the fundamental frequency for each phase of the line.
    [0191] - With these matrices the circulating currents are obtained by the neutral conductor of the load and of the three-phase source, in case there are such conductors, as well as the effective values of the direct sequence active components supplied are determined (in 18) by the three-phase source, at the fundamental frequency.
    [0192] - From the matrices of effective values of the line and neutral currents, as well as of the direct sequence active components, at the fundamental frequency, the loss reduction factor and the monitoring coefficient are calculated (in 19) of the correct functioning of the compensator, according to equations [13] and [14], respectively, for integral compensators of loads fed between phases, or, applying equations [31] and [32], respectively, for integral compensators of loads fed between phase and neutral of the source.
    [0193] - The graphic and numerical information of the loss reduction factor and the monitoring coefficient of the correct functioning of the integral compensator, as well as the effective values of the currents supplied by the three-phase source, are displayed (in 20) in a visualization device.
    [0194] The device for carrying out the measurement procedure, as shown in figures 9 and 10, is formed by a physical system for measuring and acquiring electrical signals (A) (hardware) and by a processor system (B), as well as by a measurement program (C) and by a visualization device (D).
    [0195] The physical system consists of signal conditioners and a data acquisition card. The former adapt the instantaneous values of the secondary currents of current measurement sensors (A), so that the voltages at their outputs are applicable to the analog inputs of the acquisition card or equivalent device, which converts the analog signals of voltage and intensity in a series of discrete samples that are used as input in the measurement program. Also, there is a processor system (B) with a base plate on which the acquisition card is placed so that they can be exchanged discrete samples of the voltage and current signals with the measuring program (C). It also has a display or display device (D) in which the information about the line and neutral currents supplied by the three-phase source is displayed, as well as the loss reduction factor and the monitoring coefficient of the correct functioning of the integral compensator.
    [0196] The measurement program (C) consists of the following modules (figure 11):
    [0197] - Digital signal processing module (17), which acquires samples of the line intensity supplied by the source and absorbed by the load, and stores them in a vector for each of them, obtaining the effective values and the initial phase of the fundamental frequency currents, as well as the currents of the neutrals of the fundamental current.
    [0198] - Symmetric module (18), which obtains the active components, of direct sequence, in effective value, from the currents supplied by the source, to the fundamental frequency, from the matrices obtained in the previous module.
    [0199] - Module of coefficients (19), in charge of obtaining the values of the loss reduction factor and the monitoring coefficient of the proper functioning of the integral compensator, according to equations [13] and [14], respectively, for load compensators fed between phases, or, by applying equations [31] and [32], respectively, for integral load compensators fed between phase and neutral of the source.
    [0200] - Display module (20), responsible for displaying on a screen the graphic and numerical information of the line and neutral currents, as well as the loss reduction factor and the monitoring coefficient of the proper functioning of the integral compensator.
    [0201] The invention also relates to the effective integral compensator of imbalances for loads supplied by a balanced three-phase source, which minimizes imbalances caused by energy losses in elements of said compensator, in which the susceptances of the elements of said effective integral compensator are determined by the procedure described above in the present document.
    [0202] The present invention has been described above with reference to specific preferred embodiments thereof, presented by way of example only. However, those skilled in the art will readily be able to apply modifications and variations to such embodiments without thereby departing from the scope of protection of the present invention, defined solely by the appended claims.
    权利要求:
    Claims (1)
    [0001]
    Procedure for realizing an integral integral compensator of imbalances for loads fed by a balanced three-phase source, minimizing the compensator imbalances caused by energy losses in elements of said compensator, the method comprising the steps of:
    a) calculate the complex susceptances of the elements of an ideal integral compensator;
    b) since a real integral compensator resembles the parallel connection of the ideal integral compensator of step a) and additional loads, calculate the complex susceptances of an additional loss compensator;
    c) obtain at least one of the loss conductance (Gk) and the energy losses (Pk) for each element (k) of the compensator; Y
    d) determine the susceptances of elements of the effective integral compensator, which compensates the imbalances and the reactive energy of the load, as well as the imbalances caused by the energy losses in the elements of the compensator itself. Process according to claim 1, characterized in that it also comprises the steps of:
    e) calculate the loss reduction factor (FRP%) as the quotient between the losses caused by the operation of the unbalanced load in the different elements of the system with and without integral compensator; Y
    f) verify the correct functioning of the integral compensator from the verification coefficient s between the value of the calculated FRP% with optimal values of the currents and with real measured values of the same;
    determining that the operation of the integral compensator is better the closer the value of s approaches 1.
    The method according to any of the preceding claims, the integral compensator being applied to loads fed between phases of the three-phase source, characterized in that in stage a) the complex sub-requirements of the ideal integral compensator ( Bil2, Bil23, Bil31) are calculated using any one of equations [1] and [2] below:

    in which Yx - Gx Bx are the complex admittances in each phase ( x - 12,23,31) of the load; ( PX, QX ) are the active and reactive powers consumed by each phase (x - 12,23,31) of the load; Viinea is the effective value of the line voltage (between phases), j - 1z90 ° is the imaginary unit, in the Gaussian plane; and the asterisk (*) denotes the conjugate of a complex number.
    Process according to claim 3, characterized in that in step b) the complex susceptances ( B'ix, x -12,23,31) of the additional loss compensator are calculated by any one of equations [3] and [4] to continuation:

    in which Gil2, Gi23, Gi31 are the conductances and ^ 12, ^ 23, ^ 31 are the energy losses of the loads of the real integral compensator.
    Method according to any of claims 3 and 4, characterized in that in step d) the susceptances ( Bf12, Bf23, Bf31 ) of the effective integral compensator are calculated by any one of equations [5] and [6] below:

    Method according to any of claims 3 to 5, characterized in that in step e) the loss reduction factor (FRP%) is calculated according to equation [13] below:

    in which Iez is the line current with effective integral compensator and lz is the line current without integral compensator in each phase (z = 1, 2, 3).
    Process according to claim 6, characterized in that in step f) the verification coefficient s is calculated by means of equation [14] below:

    in which Ieadz is the active complex line current with effective integral compensator.
    Method according to any of claims 1 and 2, applying the integral compensator to loads fed between phase and neutral of the three-phase source, the ideal integral compensator being formed by a star connection (with neutral conductor) and another one in delta, whose complex susceptances are ( B¡kl, B¡k2, B¡k3), for the star connection, and ( B¡1, B¡2, B¡3 ), for the entriangular connection, characterized in that in stage a) the susceptances The complex integral compensator complexes are calculated using any one of equations [15] and [16] below:


    where YZ = GZ BZ are the complex admittances in each phase (z = 1,2,3) of the load; (PZ, QZ) are the active and reactive powers consumed by each phase (z = 1,2,3) of the load; Vfase is the effective value of the voltage between phase and neutral, j = 1z90 ° is the imaginary unit, in the Gaussian plane; and the asterisk (*) denotes the conjugate of a complex number.
    The method according to claim 8, characterized in that in step b) the real integral compensator resembles the parallel connection of the ideal integral compensator of stage a) and two unbalanced loads connections, one in star and one in delta, and because the additional loss compensator comprises two connections, one in star and the other in triangle, whose complex susceptances ( B'hl, B'h2, B'h3 ) and ( Btl, Bi2, Bí3 ) respectively, are calculated by any one of Equations [17] and [18] below:


    where Ghl, Gh2, Gh3 are the conductances and Phi, Ph 2 , Ph 3 are the energy losses of the loads of the real integral compensator.
    Method according to any of claims 8 and 9, characterized in that in step d) the susceptances (B ^, B ^ 2, B ^ 3) of the elements of the star connection and ( Bf1, Bf2, Bf 3) of the elements of the delta connection of the effective integral compensator are


    Method according to any of claims 8 to 10, characterized in that in step e) the loss reduction factor (FRP%) is calculated according to equation [31] below:

    wherein lez and IEN are line currents effective integrated compensator in each phase (z = 1, 2, 3) and neutral conductor (N), lz and lN are line currents without an integral compensator for each phase (z = 1, 2, 3) and in the neutral conductor (N).
    Process according to claim 11, characterized in that in step f) the verification coefficient s is calculated by means of equation [32] below:

    where / eadz is the active complex line current with effective integral compensator.
    Process according to any of the preceding claims, characterized in that in step c) the Loss conductance (Gk) and energy losses (Pk) are calculated by equation [33] below:
    G = P = Bk'Vk [33] k QFk k QFk
    when element (k) is a coil;
    and by means of equation [34] below:
    Bk p Bk-V¿
    Gi, = [34] t g a k tQ & k
    when element (k) is a capacitor;
    where (QFk) is the quality factor, (tga k) is the tangent of the loss angle, Bk and Vk are the values of the susceptance and the voltage applied to the element k, respectively.
    14. Integral imbalance compensator for loads fed by a balanced three-phase source, which minimizes imbalances caused by energy losses in elements of said compensator, determining the susceptances of integral integral compensator elements by means of the method according to any of claims 1 to 13.
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    公开号 | 公开日
    WO2019234281A1|2019-12-12|
    ES2702530B2|2019-07-10|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    ES2169651A1|2000-02-18|2002-07-01|Univ Valencia Politecnica|Integral sequence filter for neutral electrical installations|
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