SU1610541A1 - Method of controlling capacitive compensation power - Google Patents

Abstract

The invention relates to electrical engineering and can be used in the regulation of reactive power compensation in electrical systems with rapidly alternating loads. The purpose of the invention is to stabilize the voltage throughout the network section, minimize the consumption of reactive power from the traction substations of the site and increase the service life of compensating installations by reducing the number of discrete changes in capacitive compensation power. This is achieved by measuring the voltages on the tires of the traction substations, the reactive components of their load currents, the voltages in the traction network at the places where the adjustable compensating units are connected and calculating the parameters of the equations of the simulation of the compensation process. The optimum capacitance values are determined for all compensating installations, which provide the minimum value of the control loss indicator, and are switched by sections of the capacitor installations. 3 il.

Description

The invention relates to electrical engineering and can be used to regulate the compensation of reactive power in electrical systems with rapidly varying loads, in particular, in the AC traction network.

The purpose of the invention is to stabilize the {voltage across the whole network section, minimize the consumption of reactive power from the traction substations of the section and increase the service life of the АА1 1 compensating service. (KY.) By reducing the number of discrete power variations of the capacitive compensation, 1; ii.

FIG. Figure 1 shows the scheme that implements the proposed method; . on figure 2

functional scheme KU; in fig. 3 shows an inter-station zone replacement scheme (MI3).

The circuit in FIG. 1 contains a series of interstitial zones 1 connected by a traction network, consisting of traction substations 2 and 3 and compensating installations 4, a combination of the first 5, second 6, third 7 voltage sensors and the first 8, second 9 reactive sensors the first 10 and second 11 switches, the optimizer 12, the decoder 13, the delay line 14, the first 15 and the second 16 channels of communication.

cl

four

The circuit in FIG. 2 contains a series-connected adjustable capacitor battery 17, consisting of parallel-connected 1H1 adjustable stages le and a number of adjustable stages, which are a series-connected condenser 19 and switching device 20, and a reactor 21, which are connected to the network

The circuit in FIG. 3 soderusht first 22 and second 23 voltage sources, first 24 and second 25 four polktops and rLC chain 26. Moreover, the first 22 and second 23 voltage sources are connected to the inputs of the first 24 and second 25 quadripoles, respectively. The outputs of the 24 and 25 couples in parallel are connected in parallel, and a GSF-chain 26 is connected to the -NSE.

A device reaping the proposed method for adjusting the power of capacitive compensation works as follows

I

For all inter-substation; zones

(SHZ) 1 at the outputs of the first 5 and second 6 voltage sensors generate signals corresponding to the voltages E, E at the adjacent buses of the traction substations 2 and 3, which limit the MSW 1. The outputs of the sensors 7 generate voltage signals in t of the first 8 and second 9 sensors of the reactive component of the current form the signals for the reactive 2-terminal load current of traction substations 2 and 3. The signals from the outputs of the sensors 5-9 through the communication channel 15 through switch 10 in series for all MPZ 1 is fed to the inputs of the optimizer 12. By means of the latter, the parameters of the equations for the design of the process, the compensation at the current time, and the optimal value of the capacitance of the capacitor at which the minimum value of the display is achieved are calculated;

(U) + p, 2, (Il, p | + | l2pl) + P n- p4 | u-

and

(one)

calculated by simulating the voltage at the point of connection KU j-th MPZ |

simulation-derived reactive components of yugr-ie load current

0

five

0

five

0

J-

n F (U)

substations limiting the j-th MPZ;

the measured value of the voltage in the traction network at the point of connection of the KU (j-1) MPZ; the number of switching devices of the control unit that must be switched to set the new capacity of the control device; Oh, UvHH -U UAIOKC;

g, (U-UMOIKC),. “c;

R. (u

and

min

.and.

C | COP

five

five

  , cc, is the minimum and maximum allowable stresses in the traction. networks;

J.fo,.

g sSj. I4 weights.

The first term of JJ characterizes the losses from voltage output beyond the limits of the Mox 5 interval, the second is the loss from reactive power consumption, the third is the loss from switching KU switching devices, and the fourth is the loss from voltage difference in adjacent MYSs. Therefore, minimizing control process, the indicator I ;, minimizes the reactive power consumption from the traction substations and the minimum deviation between voltages in adjacent MTtB, taking into account the limitation of switching switching devices KU and supports zhani voltage in a given interval. The priority of minimizing one or another loss is given by the weights of the patients. Since the rate of regulation losses is minimized sequentially for all LPZ units, the ESM reactive power compensation compensation mode is established on the entire power section of the traction network.

The output of the optimizer 12 generates a signal i o, T-, corresponding to the number of commuting devices 20 KU (Fig. 2), which must be closed in order to obtain optimal capacity. The signal 1d "through the 13-l deshfrator switch 11 is fed to the input of the communication channel 16, and then to the control input of the control unit 4 of that nz inter-station zone 1, the sensors 5-9 of which are connected at the current time through the switch, 0 to the inputs | optimizer 12, After generating a signal i nh the clock output of the optimizer 12 form a signal

synchronization S and serves it to control the inputs of switches 10 and 11 (to the latter via the delay line 14). The synchronization signal switches the switch 10 so that the outputs of sensors 5-9 of the next MPZ 1 are connected to the optimizer 12 inputs. The switch 11 connects the control input KU 4 of the next MPZ 1 to the output of the decoder 13 as well. regulation sequentially for

and 23 voltages Ej, Ej, the compensating set 4 is in the form of a gFC-chain; ka 26. The sections of the refinery of meztsudu substations 2 and 3 and installation 4 are shown in the diagram in B1 and 4-port 24 and 25.

In accordance with the theory of quadrupoles, the equations for their input and output currents can be written in vice:

1, a „Е, + a,;, and; 1, a, (2)

, (3)

, + B, and;

all MPZ 1. After the last M-th MPZ 1 where 1, 1 - complex values

switch 10 and 11 are switched again to the first MPZ; Line 14 of the delay is necessary so that switch 11 is switched not earlier than the signal i, the decoder 13 passed, will be fed to the input of the corresponding QU 4,

Changing the capacitance of the 1SU 4 is accomplished by switching the commutator of 1 apparatus 20 (Fig. 2). The minimum capacitance of the capacitor 4 is reached when all the commutation apparatus 20 is disconnected. In this case it remains on. only the unregulated stage 18, whose capacity is equal to C (,,

In order to increase the capacitance of the capacitor 4, the switching devices 20 are closed in series, starting from the first. In this case, the capacity of KU 4 is determined by the formula

 + CA,

where i is the number of closed devices 20;

UC is the capacitance of the condenser 19 of an adjustable stage,

The switching of the apparatus 20 is controlled by a signal U, which is fed to their control 1 × 1e inputs. The signal is an N-digit digital code in cooTBeTCTBkm with N controllable steps KU 4,

20

25

thirty

35

40

input currents of four poles, which fall from the currents of the loading substations; 1 - complex values of fourfold lusnikov current currents;

and - the output voltage of four-pole devices, which coincides with the voltage at the connection point of the capacitor bank;

) IJ - parameters of four-fields, which are complex numbers, the parts of equations (2) are

1, p «.iR, +, E + (XjzU whereЫ;) fU; j, b; j, 1ri); U | and (, Срц а

From the replacement circuit (.fig. 3) ime

(i, + i4), where is the impedance of the capacitor;

g, G-- - active and reactive

resistance KU; L - reactor inductance

1SU;

M

С - capacitor capacitance of the battery KU in the current ment of time.

Substituting in (5) equations (3), 45, we get

ISjllllklL ll (

T-zIa t + bzi)

The simulation equations for the reactive power compensation process are obtained on the basis of the replacement scheme

(Fig. 3). On it, the power substations of 2 50 live and real parts, and 3 are presented as sources 22

Enter the notation a, A, | - «- j / g; bzt, R., Split, E ,, r-lVx + y. Izio + EtLj i. G-yyy + U112 (0. (- ,.

.., (7)

„E. X-t-rr + rJz / l-l-EzCai. X-bJ322r + r.iziil., 04

() 5-; n ;; ; i lr)

quadrupole input currents that coincide with the load currents of the traction substations; 1 — complex values of the output currents of the quadrupoles;

and - the output voltage of the quadrupoles, coinciding with the voltage of the network at the place of connection of the capacitor;

) IJ - parameters of quadrupoles, which are complex numbers, part of equations (2) are equal to:

1, p «.iR, +, E + (XjzU (whereЫ;)) fU; j, b; j, 1р); U | and (, Src arr, and.

Of the replacement circuit 1 (.fig. 3) we have

(i, + i4), where is the impedance of the capacitor;

g, G-- - active and reactive

resistance KU; L - reactor inductance

1SU;

M

С - capacitance of the capacitor battery KU at the current time.

Substituting in (5) of equation (3), we will learn

ISjllllklL ll (6)

T-zIa t + bzi)

U

The real and the useful parts, according to

Enter the notation a, A, | - «- j / g; bzt, R., Section 716

where I z j is the impedance modulus j

I - (3u,); f .- (Mi AC (,; (G4 rLg + / z. (5 ,.

For voltage U is fair expression

.., Ill Ht

(9)

.

The obtained equations (4), (7) - (9) are the equations of the simulation of the reactive power compensation process in the EMF, i.e., the mathematical model. The input information for it is the voltage E, K of the traction substation and the capacitor battery KU. Capacitance C is a controlled input action, as it varies. The output information in the resulting model is the voltage U at the connection point

KU and reactor components of load current of traction substations. The model includes the parameters: oi, j ,, - j,. J, 1, the values of which are a priori unknown and vary over time mainly due to the traction load.

Using the model obtained to control the power compensation requires a preliminary determination of the parameters of the simulation equations.

When determining the unknown parameters of the model, it is necessary to find their values, ensuring the minimum deviation of the output variables U,, Ign of the model from the corresponding informative variables U, liDH of the real process, measured by sensors 7.8 and 9, T, e. determination of the parameters of the small pox / body based on the requirements of the best adequacy of the peajibHOMy model to the process of compensation of reactive power in the MSW

t

The degree of deviation of the model and process variables is estimated by the error function of the form:

1 Y / -y 5, yyy -,) 2 + p, (Uj ,,

l4 (I, p, -I ,.) + Cl U),

ri ip ip

-I.

(ten)

where g is a weighting factor equal to the ratio of the average variance of the reactive components of the load current to the nominal; apr in the traction network. The required parameters should be determined from the minimum of the function D1 and error I, i.e. of the conditions. (".) O /; i, p,;, 1

0

five

0

18

(the parameters y-; are uniquely determined by the quantities fi ;:; 5;).

To achieve a minimum, the funktsi I parameters and ;:; P ;;, 5;, having changed in time, should be adjusted so that, starting from a certain initial value, they reach values that ensure the performance of the ulo. . Viy (11). This is necessary so that when adjusting the parameters, they move along the anti-gradient of Function I, i.e., in the direction of its most rapid decrease.

Then the equations for adjusting the parameters take the form:

  cC / L -i - || -;

(;.,;

(12)

(13)

five

0

0

five

0

 - 2, 2

where the argument in square brackets denotes the number of a discrete point in time, t, e. tact

Substituting expressions for partial derivatives, we have:

. (х „И„ Гк-Г1 + Е, к (1, р, 1, (15)

Ы, г Н п к-1 (1, ри к - 1, р к); 5 Va, С К Ы 2, К-1J + RZ к (1g РИ) 5

about (0 ((Q)).

pt-a G- L + P lMASHt GkKg- „LKJ-rp l -1J -u K A

-S i; K - i to (jz | 4j;.

(sixteen)

P. .., K (X. + J) K-1 z P) -Up HA (r-UK-I I zp);

(-E, (x-bS,);

 § ... 4, -1 | zi -Ui LKJ (r-, CK-1 gP),

§, Kj4 ,.

C, K 5 "K-11N-IR K, GGK-0 - hi f

-1J) (, fz | 2-r); (17)

16105

5, k ,,.,. 5.1Ш, (irGfigk-1 - i to p, k-1) -

(,, -l) (,

(one,,).

0 (with TO (1, p) ();,

A (1-5,) 2 + (J,.

Parameters are calculated by the formulas:

)((,,to);

(18)

(,. ,,, Гк);

, 20

1 4GK city, GK.

The values of the variables "Gk7, and ,, Gk1:, 1, pSK, I, I, BxSiJ e L-, 5 are better formulas for calculating the parameters, are calculated with the help of the simulation equations, substituting the values of the parameters calculated on the previous one (К -1) th tact:

, And (|%, ,, °

if.) + E, K (pa ,,, K- -1 x- corner K-11 (dM) (1y)

 M (Gk-Ya) x (Y k-1 | r | H + E, k (p „Gk-1 xh- | 2,); C20)

IMNs |,

. (2)

I, р К „к-1 Е, М + с ,, к-1 and к;

(22)

40 (22)

15 о W О (г, Гк-1 Ч к-1 and к. U3)

The initial values are); and the parameters at are taken equal to zero, i.e.

, 2; , 2.

The calculation of the parameters and the optimal values of capacitances of the QU 4 is performed using the optimizer 12. At each discrete point in time, the parameters of the equations of the model are calculated for all MPW 1 of the plot, in accordance with the formulas obtained. Rowash, as well as the values of the indicator (1) for all possible

your KU capacitance values. The optimal value is taken to be the capacitance value at which the control loss indicator (1) takes the minimum value. Optimizer 12 can be implemented on a digital computer. In the algorithm of its operation, a series of quantities (model parameters, CG parameters, control loss rate) will be denoted with the index J, which indicates the number of MPZ and takes values from 1 to M.

The algorithm of the optimizer 12 has the following 1st view.

1. Set parameters KU and SHZ: active resistance z j; inductance L;

J, the capacity of the unregulated stage capacity of one adjustable stage i.C; the number of adjustable stages Nj; the number i p 1 of the included KU adjustable steps at the initial moment of time and the initial values of the parameters:

. )

 1 1.2; j T7M. 2. Calculate the initial capacitance KU all Sh13

, j i, M.

3. Install the clock counter.

4, Form a loop on a variable from

1 to M, input from the switch 10 values of informative variables on the Kth cycle

40

Е, Е, and „1,.,

to,

Q

and reset the sync signal.

5. Calculate X ULi-1 / (i)

(..

6. Calculate the values of the variables; si; Three; I to according to the formulas (19) - (23).

I 7. Calculate parameters A short; BUT;

; eI; | 3ieM ji to according to the formulas (15) - (18).

8. The initial value of the control loss indicator is set, which is obviously greater than the real values.

9. Form a cycle in variable i from O to NJ and calculate the corresponding capacitance:

С1ГК + Г | C -1.AC X, fz /.

10. Calculate the number of switching devices of 20 K, which is not necessary to switch, in order to replace the capacity with DO to set the capacity, calculated in paragraph 9:

p-4tGk1 5

11. Calculate the values of the variables aM; si; 1, And about the formulas (19) - (23) for the capacity GK + lJ, replacing the parameters in them

.

) fJ Gk1, obtained in paragraph 7.

Mz. If ulKl UMakC5, then calculate

F (U) p, / U K -UMaKc).

13. If UTKl-UjwyiH, then calculate

F (U) g. (U, H-uri94 14 .. If (, i and II, 6, “with .to ask

F (.U) 0.

15.If, then, they calculate 20 I. 17 (U) + d, (} 11 CZ -11 tp Kl I) + B

16.If, then, (U), pDqM- | l ,, n

g luH-ui- to .25

, 17, If the condition ij is fulfilled

il, .i5; ioV K-il- with “,, sgk-11;

and

wholesale

18. Close the variable variable i. .nineteen. An optimal capacitance of 30 KU is formed for each;

wholesale

Gk-yb

20. Form a view signal of synchronization, close the cycle in a step. belt j.

21. Set the next tact number.

22. Go to step 4.

Thus, the algorithm of the optimizer is conditionally divided into four 40 parts. In the first of them (PP.1 and 2), the parameters of the sicex KU and the initial values of the parameters of the model are set. In the second part (pp, 3 - /), the parameters of the 4j model equations on the Kth cycle for the jth SZ are calculated. The basic input data for this part of the algorithm are the variables entered in step 4. In the third part of the Osh algorithm. 8-17) the method 50 of direct enumeration of all possible discrete values of the capacitance KU of the jth SHZO is realized. IJ is minimal

Wholesale

equal to 10% capacity

Corresponding to the value of 1d, K + 1, corresponds to the voltage in the connection point of the AC for this case.

Corresponding to the choice of weight coefficients R, g, j; , g4 indicator of regulation loss (1), you can set the required priorities in minimizing one or another component of losses. For example, ruble losses caused by nonzero values of the terms included in.

Claims (1)

Invention Formula The method of adjusting the power of capacitive compensation in the traction from the network, based on a discrete change in reactive power generated by transverse compensation TaHOBKaNffl within the inter-station zone (MPZ), at which the currents of the heavy, - out substations and voltages inside the interconnection zones are measured , calculate the parameters of the reactive power compensation process models and determine the optimal values of the capacities of all the components of the JJ x installations, ensuring the lowest value of the control loss indicator that differs from In order to stabilize the voltage throughout the network, minimize the consumption of reactive power from the traction substations of the site and increase the service life of compensating installations by reducing the number of discrete changes in the power of capacitive compensation, the voltage on adjacent buses is also measured. traction substations and determine the optimal values of the capacitances for all the co-generators by successively calculating the control loss rate for all possible capacity setting and, as the optimal one, take the one at which the control loss rate is minimal to have for the jth in-substation zone the form (U) -fR, (I 1, p | + fl gr i) 1 where and is calculated by-mode-. line voltage in the traction network at the connection point of the considered compensating installation; 13 . I is the value of the reactive composition. obtained by simulating the process of comp. f., pens; - the measured value of the voltage in the traction network at the connection point of the compensating installation (I-1) -th interstation station; oh, um "and-and ,,; F (u) and Th | i-imocs), IB, (UMHH-U),, “and max is minimal and maximally admissible on FI2. f Yu | 5 14 yarns in the traction network; J p. :  (s “,   weights; n is the number of switching devices of the compensating installation, which is neo-necessary to switch to install the new value of the capacity of the compensating installation.  2 L uz 3 .L