Voltage stabilisation system at extended power transmission line. RU patent 2520311.

FIELD: electricity.

SUBSTANCE: voltage stabilisation system contains a transformer substation and an aerial transmission line with power supply branch lines, three independent voltage adders at each of the phase lines installed at the end of the last line, at that the voltage adder is made as a bridge circuit, two parallel interconnected branch lines, which consist of in-series accumulating LC delay line and bidirectional transistor-based commutator, in the bridge circuit diagonal there is an installed bidirectional triode thyristor, accumulating LC delay lines of the bridge circuit branches are connected to phase and zero wires respectively.

EFFECT: stabilisation of the network voltage along the whole line of the power transmission line at variable load of the consumers connected to it.

2 cl, 6 dwg

The invention relates to the electrical engineering and may be used mostly in rural areas, and gardening associations when using transformer substations (TS) relatively low-power (100...150 kW) and at considerable length Laden air transmission lines (0.4 kV), the end of which the voltage drops to invalid values up to 170 In and below the permissible size not worse 200 Century

There are ways to counter the lower voltage at the end badly enough electrically loaded transmission lines by improving cross-section of the conductors of 0.4 kV, which increases the cost of such lines, and increasing voltages from the output of the TA to unacceptably large values (for example, more than 230).

These shortcomings known methods of equalization voltage along a transmission line is fixed in the proposed technical solution.

The aim of the invention is the alignment of voltage on all length of a transmission line when changing the load connected to her subscribers.

This goal achieved in the present system voltage regulation longest transmission line containing transformer substation and air-line of an electricity transmission with branches of power supply to the subscribers, characterized in that it includes three independently operating device volt-additives for each phase three-phase transmission line, installed at the end of last device volt-supplements is made in the form of the bridge circuit, two parallel between the branches which are composed of series-connected cumulative LC-delay lines and bidirectional transistor switch, in the diagonal bridge circuit is installed triac, cumulative LC-delay lines branches of the bridge circuit, respectively connected to the phase and zero conductors of a transmission line, bidirectional transistor switches are a pair of transistors one type of conductivity, for example, n-R-n, opposite parallel with the United transitions collector-emitter", full capacity of each cumulative LC-delay line with a time delay of about 2 MS selected consistent with the highest power consumption subscribers transmission lines, and management charge capacitors cumulative LC-delay lines in the first and third quarters periods voltage network and their discharge in the second and fourth quarters periods voltage implemented from synchronized with the voltage of this phase control unit transistors and triac, and change the time of the capacitor charge cumulative LC-delay lines in the process of stabilization of voltage under dynamically changing load of connected subscribers implemented static system of automatic regulation (with nonzero residual error), including standby multivibrator loader pulses with variable them exceed t ZAR =1...5 MS, controlled field-effect transistor as a variable resistor under the action applied to its transition "gate-source" DC voltage which is proportional to the current network voltage, also, the inclusion of the triac in the second and fourth quarters periods voltage at which the capacitors both cumulative LC-delay lines are connected in series to phase and zero conductors network, forms discharge current back into the network, compensating thereby energy losses in transmission lines.

This the control unit of transistors and the triac includes synchronized mains voltage on this phase pulse generator is included in the first and third quarters periods of voltage corresponding pairs of transistors in the branches of the bridge circuit with adjustable duration, provided to the rectifier control a network of an alternating voltage is removed from secondary winding of the transformer, consistently included Zener diode reference, a low-pass filter and adjustable divider DC control voltage and generator trigger pulses the triac in the second and fourth quarters periods of voltage.

The achievement of this goal the invention is explained by periodic charges and perezarazhenie parallel to include cumulative LC-delay lines from the low to the end of the line voltage in his first and third quarters periods and for discharge and pererastala these consistently included cumulative LC-delay lines back into the network in the second and fourth quarters periods, which increases medium-current mains voltage on all length of a transmission line, but with some loss of symmetry of the shape of the voltage (different from harmonic) if the condition coordination of energy parameters used cumulative LC-delay lines (capacity capacitors) with the greatest possible power consumption of electricity subscribers of the power line. The use of elements of automation allows to stabilize voltage under dynamically changing load created by subscribers connected to the power line. It is fundamentally important that the connection is claimed stabilization system implemented at the end of a transmission line that enough is equivalent to setting the virtual transformer substation at the end of a transmission line, fed on the existing transformer substation, located at the beginning of this line.

The inventive system voltage network is explained in the accompanying figures. 1 presents the scheme of connections TA, 0.4 kV with loading its subscribers and three parallel and independently working devices volt-supplements HC-1 (2, 3) in the presence of all three phases in the line Number of devices HC is determined by the number of working phases at the end of the transmission line (if not all three phases laid before the end of the line).

Figure 1 presents:

1 - transformer substation (TS), which convert three-phase current with a voltage of 10 kV current with a voltage of 220 V at each of the three phases and is connected by wire (five-wire in the case of provision of street lighting) air lines of 0.4 kV with branches;

2 - subscriber structure along 0.4 kV,

3 - volt device-supplements HC-1 (2, 3) for each of the phases a, b and C line VL,4 kV.

Figure 2 shows a diagram of the device volt-additives, for example, in phase A, containing the following elements and units:

4 - the first cumulative LC-delay line for 2 MS

5 - the first bidirectional transistor switch,

6 - second bidirectional transistor switch,

7 - second cumulative LC-delay line for 2 MS

8 - triac included in the diagonal bridge circuit,

9 - power transistor control and the triac.

Fig.3 shows a functional block diagram 9 transistor control and triac containing the following elements and modules:

10 - the first adjustable divider network phase And,

11 - the first comparator with logic level "0" and "1" output,

12 - the first inverter

13 - the first trehlitrovuyu scheme matches (3I),

14 - a two phase-shifting RC-circuit, adjustable phase AC line voltage 90±5 degrees,

15 - second adjustable voltage divider network in phase A,

16 - second comparator with logic level "0" and "1" output,

17 - the second inverter

18 - second trehlitrovuyu scheme matches (3I),

19 - the first pulse amplifier

20 - the first transformer cascade connection with the included transistor bridge circuit in the first quarter of the periods of voltage,

21 - second pulse amplifier

22 - second transformer cascade connection with the included transistor bridge circuit in the third quarter periods of voltage,

23 - the first summarizing shaper short pulses, is bound by time to the beginning of the first and third quarters periods of voltage,

24 - pulse shaper start (enable) the triac 8,

25 - second summarizing shaper short pulses, is bound by time to the beginning of the second and fourth quarters periods of voltage,

26 - the pulse shaper shear Dt add =0.2 MS,

27 - shaper short pulses, is bound by time to a decline of pulses shift,

28 - shaper impulses run triac with duration t REC =1...2 MS,

29 - third pulse amplifier

30 - the third transformer cascade connection with managing the transition the triac 8 in the second and fourth quarters periods of voltage,

31 - secondary power supply (VIP) with the output stabilized voltage -6 V, +5 V and +15 C.

Communication unit 9 with the elements of the bridge circuit shown in figure 2 and 3 of the lowercase letters of the Russian alphabet.

On figure 4 presents diagrams of signals at different points of the control unit transistors and triac, namely:

4A - at the exit of the first comparator 11 - signal And,

4B - at the exit of the second comparator 16 - signal, _

4B - output first trehvaltsovoj scheme matches 13 - signal And*In,

4G - on the second trehvaltsovoj schema matching 18 - signal And*In,

4D - at the exit of the first inverter 12 - signal And,

4E - at the exit of the second inverter 17 - signal,

I - on the second summing shaper 25,

S - output driver 28 trigger pulses triac 8,

4I - plot network voltage u (c (t) when running system stabilization

4K plot phase current i f (t) (forward and reverse, estimated).

Figure 6 shows a diagram of related modules 23 and 24, containing a pair of generators of short pulses of duration Dt KI =10 ISS, is bound by time to wavefronts formed at the outputs of the first 11 and 16 second Comparators logic level "0" and "1", summarizing the module with inversion, the output of which is formed impulses that are bound to the beginning of the first and third quarters periods of voltage waiting multivibrator with adjustable duration charging pulse t ZAR =1...5 MS with time-specifies RC-circuit, a resistor which is made on the basis use field-effect transistor with his running DC voltage proportional to the network medium-applicable for the full period of the mains voltage, upon receipt of this control DC voltage by a full-wave rectification of alternating voltage with a reduction of the transformer is connected to the network, subtract fixed voltage, filtering rectified voltage in the two-tier lowpass filter and tuning control voltage resistive divider taking into account the capacity of the condenser time-specifies RC-circuit standby multivibrator. As standby-flop can be used chip type CREW, and as an automatically controlled voltage resistor time-specifies RC-circuit standby multivibrator can be used in field-effect transistor CPU voltage control "gate-source" in the range u SID =0,8...1,5 V At the effective value of a voltage of a network for the first and third quarters of the periods of the supply voltage in the range of 170 to 220 V or what is the same, when you change the medium of current mains voltage in the manufacture of its stabilization within 218...222 Century

Consider the effect of the applied voltage regulation on example of work of the device volt-supplements diagram in figure 2, one at any phase of 0.4 kV, for example, in phase A. Schemes HC-2 and Il-3, connected respectively to the phases b and C networks are structurally similar scheme HC-1.

Let us assume that during the first quarter of the period mains current flows in phase And follows the zero conductor, and in the third quarter of the period, on the contrary, flows on a zero conductor and follows by induction. Charging of the capacitors cumulative LC-delay lines 4 and 7, parallel to the network occurs in the first quarter of the period due to open transitions collector-emitter" upper circuit of the transistor n-p-n - type comprising bidirectional transistor switches 5 and 6. When the delay time in the iterative cumulative LC-lines delay of about 2 MS by the end of the first quarter of the period of voltage on all capacitors these lines 4 and 7 reaches a certain value U*≤U O depending on the duration of the open condition of these transistors in two branches of the bridge circuit, where U O - peak value of the mains voltage to consider the first quarter of the period.

For example, if the current value of a voltage of a network for the specified time range 170 In (including loading transmission lines) About U =1,41 * 170≈240 Century This voltage U*=U, provided that the switching charge transistors remain open throughout the quarter period, when the pulse duration, opening the appropriate transistors, equal t ZAR =5 MS. With a minimum duration of these pulses (of the order of 1 MS) capacitors do not have time to recharge voltage U About .

At the beginning of the second quarter of the period, with some delay Dt add =0.2 MS necessary to ensure reliable, closing all transistors bridge circuit, in particular, the above transistors, open in the first quarter of the period, opens triac 8, which both cumulative LC-delay lines 4 and 7 consistently, and to phase and zero conductors network is applied twice the voltage charged capacitors 2U*, in which the discharge current with these capacitors acts in the opposite direction, increasing the amplitude of the voltage in this interval of time (about 4 MS) on the value ΔU addition to the amplitude U About , as shown in rise. The capacitor discharge ends, and triac 8 closes automatically when the corresponding flowing through it is the minimum current in accordance with physics work triacs (as thyristors). With triac 8 closed some time before the end of the second quarter of the period for the time Dt closed , as shown in Risi, i.e. before the opening of the corresponding pairs of transistors bridge circuit.

In the beginning of the third quarter of the period, there is an overcharge of capacitors cumulative LC-delay lines 4 and 7 of the applicable network low voltage with an amplitude - U On with open bottom of the scheme transistors bidirectional transistor switches 5 and 6. The voltage on these capacitors reaches values - U*, as in the case of the charge in the first quarter of the period, but with the opposite sign.

In the beginning of the fourth quarter of the period, with some delay Dt add =0.2 MS opens again triac 8, and twice the voltage - 2U* is applied to the wires network, as can be seen from rise. After completion of discharge of these capacitors in the network triac 8 automatically closed.

In all other periods indicated processes charge-recharge and discharge-overdischarge cumulative LC-delay lines 4 and 7 is repeated.

The presence of amplitude of a voltage-supplements ΔU valid in the second and fourth quarters of periods to compensate for insufficient for users of electricity amplitude U About . effective in the first and third quarters periods. This distorted from harmonic form voltage has a medium-effective value CP U more than U O /1,41, but less than U O +ΔU)/1.41 for that is close to the value of 220 Century The inequality U O /1,41<U CP <U O +ΔU)/1,41 reflects the essence of the proposed technical solution. An actual value for U CP is quite difficult by averaging time of the half-period T/2 instantaneous values u (C (t) in the integral form:

moreover, u (C (t) has a complex structure in its analytical representation as a function of time. The peak value of the voltage is 2U*=480...490 Century

The presence quasiplasma peaks in the plot rise for voltage capacitor discharge cumulative LC-delay lines (in the second and fourth quarters of periods) due to the physics of action iterative cumulative LC-delay lines, spanning the discharge and supports output voltage practically unchanged during the entire time delay (in this case for 4 MS, since both lines at their discharge is connected in series). If only capacitors, instead of LC-delay lines, with the same energy of charged capacitors, their discharge would be exponential and with a very large initial shock of the discharge, which may be dangerous for the integrity of the used triac. In addition, while there would be an increased level of interference. These circumstances justify the use of iterative cumulative LC-delay lines, instead of only the capacitors in bridge schemes volt-additives.

Is flowing phase current during operation HC-1 shows the approximate plot on risk. See, in particular, that in the second and fourth quarters of the period the direction of the current phase is reversed compared with the currents for regular active loads of subscribers, and indicates that the recharge of transmission lines of action of the device volt-supplements HC-1.

Note that the distortion of voltage and current in the network when working claimed device does not render practically any negative effects on household appliances subscribers - televisions, refrigerators, lighting equipment and electrical heating. A more sophisticated technique subscribers, for example, computers are also protected from the actions of emerging low-frequency interference, since these devices have the appropriate filters.

Let us now consider the operation of the control unit transistors and triac, functional diagram of which is given in Fig.3 and explains temporary diagrams in figure 4.

The purpose of this unit is dispatching processes of opening and closing of transistors and the triac bridge circuit (figure 2) at the right times during each period mains duration T=20 MS (with the frequency of 50 Hz). The latter determines the timing of this process mains voltage on the selected phase. Reference time points for the work of the unit are the initial phase alternating voltage phase Phi=0 and phase Phi=PI/2. The first anchor point with the phase Phi=0 is used in the block itself, and the second requires the phase shift of the mains voltage for this phase And angle Phi=90 degrees. The latter is achieved by using an adjustable two-unit RC-chain 14, connected to the phase conductor (b) network. After the relevant regulated voltage dividers 10 and 15 variables voltage with a phase difference between them on PI/2 affect the first 11 and the second 16 Comparators, the output of which formed meander sequence logic level "0" and "1" shown respectively Rica and 46, referred to as the logical signals a and B. At the output of the first 12 and 17 second inverters arise logical signals a and b shown in rid and 4th. From the combination of these four types of signals can be distinguished impulses transistor control and triac at the right time and with the required duration of each period.

Thus, to obtain pulses opening the corresponding pairs of transistors in the first and third quarters of the period of use logical operations And, * and * performed using logic "3I-NOT" 13 and 18 associated with the logical elements respectively 11 and 17, as well as 12 and 16. This adjustment of the duration of these pulses t ZAR determining the duration of the capacitor charge cumulative LC-delay lines 4 and 7, is carried out by the third logical inputs items 13 and 18 from managed standby multivibrator in the module 24 triggered by short impulses, time-bound basis of the first and third quarters of the period. The formation of these pulses charge shown respectively RISU and 4G indicating for simplicity only perform logical operations And, * and*, that is, without specifying in conjunction with the control signal duration of these pulses (the latter is shown by arrows in downturns these pulses). Enhanced capacity in the modules 19 and 21 and isolated electrically separate pairs of output transformer windings 20 and 22 impulses opening of transistors affect their respective transitions "base-emitter voltage, as shown in figure 2 and figure 3 (referred to in lowercase letters of the Russian alphabet).

The formation of start-up pulses triac (points in his opening) by modules 25-28, followed by the rise of the received pulse start in module 29 with transformer output 30, the secondary winding of which is connected with the managing transition triac 8. Figure 5 gives the PFN run the triac. Because this scheme generates pulses that are bound in time to the beginning of the second and fourth quarters of the period, with some time delay Dt add ≈0.2 MS to provide reliable, closing all transistors bridge circuit by the moment of opening the triac 8, the schemes are consistently connected summarizing the second driver of short pulses 25, bound in time to the beginning of the second and fourth quarters periods of voltage, two conditioners (working from outputs items 16 and 17) short pulses, is bound by time to the beginning of the second and fourth quarters periods of voltage, with a summing device driver 26 pulses shift Dt add =0.2 MS, additional driver 27 short pulses, is bound by time to a decline of pulses shift, and shaper 28 impulses run triac with duration t REC =1...2 MS. Outdoor these impulses triac continues to be in a conducting state with very low resistance (tenths and hundredths of Omagh, depending on the type of high-current triac) as long as the current through it reaches the minimum passport level.

Let the average statistical most consumed by subscribers capacity is R MAX =30 kW per phase when using TP 100 kW for three phases. Then the energy stored in the capacitor both cumulative LC-delay lines 4 and 7 for half of the period of T/2=10 MS, when the capacitors these lines are charged to the amplitude of the voltage U O =240 V (at current voltage at the end of a transmission line, 170 In the first and third quarters periods of voltage), is W Σ =P MAX T/2=3 * 10 4 * 10 -2 =300 J., that is capacitors in each cumulative LC-delay line store greatest required energy 150 J.. When the voltage U =240 In this energy corresponds to the capacity of all capacitors in each of the delay line With Σ =W Σ /About U 2 =300/240 2 =0,0052 f=5200 international film festival. We will use the delay lines capacitors type K75-1 capacity of C 1 =200 PF to operating voltages of 400 Century, Then in each line delay the number of links is n=5200/200=26 links. With a total delay of a line is equal to 2 MS latency of each link is Δτ 1 =2 V / 26=76,92 ISS. By the well-known formula for the time delay Δτ 1 =2π(LC) 1/2 is easy to find the value of inductance L 1 (link, which is equal to L 1 =(Δτ 1 /2π) 2 /C 1 =(76,92/6,28) 2 * 10 -12 /2 * 10 -4 =75.10 -8 GN=0,75 mH. This inductance is a single-layer winding wires of several turns, which can be calculated by the formula of Napoca L=10 N D 2 /[i/D)+0,44], where all dimensions in inches (1 cm inductance equal 0,0009 uh), N is the number of turns of the coil, D and i - the diameter and length of winding coils. Search inductance is responsible coil of 5 turns with the appropriate step between them. The average current of charge in each of the delay line for the period is not more than 70 A. Then the diameter of the copper coils in the links LC-line at the current density of 10 a/mm 2 is equal to 3 mm

As transistors in the bridge mode, you can use silicon power transistors type TCD-100-6-1 with the operational current up to 100 a and allowable voltage 600 V (allowable pulse current of at least 150). As the triac can be used triac type TC-151-160 class not lower than eighth (800), with operating current 160 Atransition and triac cooled with radiators with an area of their surface S, calculated by the formula S=R RACES q, where P RACES - power dissipation in the transistor or triac (W), q - surface density of radiation (usually accept q=20 cm 2 /W without forced cooling with ventilators).

In the power lines, the number of operating phases in which varies according to the length of the line that is often found in practice to save the conductors of 0.4 kV, the device volt-supplements to the relevant power P MAX can be set at the end of each breaking phase (b and C) of such transmission lines.

It should be noted feature of the work of the claimed device. If the meter in the TA applied the old induction type with rotating disc, if consumed by subscribers power is less power P MAX which is designed for a device volt-additives, the disk meter will spin in the opposite direction, reducing the testimony of the energy consumed.

1. The system of stabilization of voltage on the long transmission line containing transformer substation and air-line of an electricity transmission with branches of power supply to the subscribers, wherein consists of three independently operating device volt-additives for each phase three-phase transmission line, installed at the end of last device volt-supplements is made in the form of the bridge circuit, two parallel between the branches which are composed of series-connected cumulative LC-delay lines and bidirectional transistor switch, in the diagonal bridge circuit is installed triac, cumulative LC-delay lines branches of the bridge circuit, respectively connected to the phase and zero conductors of a transmission line, bidirectional transistor switches are a pair of transistors one type of conductivity, for example, n-R-n, opposite parallel with the United transitions collector-emitter", full capacity of each cumulative LC-delay line with a time delay of about 2 MS selected consistent with the highest power consumption subscribers transmission lines, and management charge capacitors cumulative LC-delay lines in the first and third quarters periods voltage network and their discharge in the second and fourth quarters periods voltage implemented from synchronized with the voltage of this phase control unit transistors and triac, and change the time of the capacitor charge cumulative LC-delay lines in the process of stabilization of voltage under dynamically changing load of connected subscribers implemented static system of automatic regulation (with nonzero residual error), including standby multivibrator loader pulses with variable them does not exceed 1...5 MS, controlled field-effect transistor as a variable resistor under the action applied to its transition "gate-source" DC voltage which is proportional to the current network voltage, also, the inclusion of the triac in the second and fourth quarters periods voltage at which the capacitors both cumulative LC-delay lines are connected in series to phase and zero conductors network, forms discharge current back into the network, compensating thereby energy losses in transmission lines.

2. Device claim 1, characterized in that the power transistor control and triac includes synchronized mains voltage on this phase pulse generator is included in the first and third quarters periods of voltage corresponding pairs of transistors in the branches of the bridge circuit with adjustable duration, provided to the rectifier control a network of an alternating voltage is removed from secondary winding of the transformer, consistently included Zener diode reference, a low-pass filter and adjustable divider DC control voltage and generator running pulse the triac in the second and fourth quarters periods of voltage.