RU2568936C1 - Electric meters operation scientific instrument - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: instrument comprises a bridge circuit coupled through the tested electric meter to the AC mains, and this bridge consists of two parallel branches of in-series storage capacitor and power transistor with in-series thyristor (bidirectional triode thyristor) and inductance coil (choke) switched on into diagonal lines of the bridge circuit. At that in the first branch of bridge circuit the storage capacitor is coupled to phase conductor while in the second branch the power transistor is coupled; besides the instrument includes control unit for power transistors and thyristor. At that unipolar compact and energy-intensive electrolyte capacitors are used as storage capacitors, and in the control unit for power transistors and thyristor rectangular pulses are generated for power transistors opening with duration of (T/4)-ΔT, where ΔT<T/16, for each positive half-period of the mains voltage, as well trigger pulses are generated for the thyristor delayed in time from instants of time of (T/4)-ΔT in each positive half-period of the mains voltage per a small value of Δt_del = ΔT-(Δt_pulse/2)<<T/16.

EFFECT: simplified design and improved energy efficiency.

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Description

The claimed technical solution was created with the aim of instructing the energy supplying organizations to completely replace the fleet of induction metering devices without the backstop of rotating aluminum disks of the СО-2М type, which are still widespread throughout the country, since they allow the theft of electricity by the so-called rewinding of rotation reversal readings drive, as well as with the aim of developing electric meters that do not contain an element of multiplying the current values of the mains voltage and current in the active load As is the case at present in almost all types produced counters for active energy, including electronic electricity meters.

It is known that the inclusion of a capacitor with a capacity of C in the network does not change the readings of the active energy meter, since in this case the electricity circulates in the network with a double frequency. Moreover, in the first quarter of the period of the mains voltage, such a capacitor is charged to the amplitude value U (for a 220 V network, the amplitude is U = 310 V), and in the second quarter of the period it transfers all its charge back to the network. In the third Thursday of the period, the capacitor is recharged to an amplitude value of U = -310 V and in the fourth quarter it again discharges completely back to the network. The capacitor charge current in the first quarter of the period (or overcharge in the third quarter of the period) changes from zero at t = 0 to the maximum at t = T / 8, where T is the period of fluctuation of the mains voltage, and then towards the end of the first quarter of the period at t = T / 4 again becomes equal to zero, since the capacitor manages to charge up to the amplitude voltage of the network U, given the low resistance of the power source and power line. This significantly distinguishes the current when charging the capacitor to the amplitude value U at the end of the first quarter of the period from the current in the active load, in which the current, on the contrary, increases with increasing voltage and is maximum at t = T / 4, and is equal to I _MAX = U / R, where R is the resistance value of the active load.

An electric meter calculates energy by multiplying the instantaneous values of current and voltage and integrating the result of such multiplication for any arbitrary period of time. If we assume that the energy for the first quarter of the period 0≤t≤T / 4, consumed in fact for the charge of the capacitor C and for heating the resistor R, is the same, then taking into account the difference in the change in currents during the charge of the capacitor C and when passing through the resistor R as a function of according to the harmonic law of the mains voltage, it can be shown that the meter responds differently to these loads, underestimating the readings of the energy it takes into account for a quarter of the period when the capacitor is charged, compared with the case of connecting an active load, which is clearly seen from comparing the following integrals

- при включении активной нагрузки,

- when you turn on the active load,

- при включении конденсатора.

- when the capacitor is turned on.

Consequently, for the same energy consumed is actually a quarter of the period of the countdown it is different: electric meter readings lowers energy consumed by connecting the condenser to the 0.785 / 0.667 = 1.18 times as CU ^2/2 = ² the TU / 8R, ie when the equality of the energy consumed in the capacitor C and in the active load R.

This difference in counting allows you to create devices for “winding up” the readings in the meters when using capacitors as a buffer consumer of electricity, consuming electricity as a capacitive storage device and transferring the same energy back to the network in the same half-period in a time interval near the highest instantaneous voltage value, namely the interval (T / 4) -ΔT≤t≤ (T / 4) + ΔT, where T is the period of the alternating voltage of the network (for example, Τ = 20 ms), ΔT = (t _IMP / 2) + Δt _REF , t _IMP - length of the capacitor discharge pulse back to the network, Δt _REF - a short delay time from the end of the capacitor charge during the time t _ZAR = (T / 4) -ΔT until the start of the discharge pulse with duration t _IMP (see Fig. 2). During this interval of the discharge of the capacitor into the network, the voltage is near the amplitude value U with a small spread from the value U _Δ to U, where U _Δ = Usinω [(T / 2) -t _UTI ) / 2], where ω = 2π / T - Circular frequency of the mains voltage (e.g., ω = 314 Hz). It is clear that the above integral relations show that the readout in the charge energy meter is reduced by 1.18 times with respect to the discharge energy, that is, about 18% of the electricity can be consumed UNCONSIDERLY, and with respect to any produced types of meters using instantaneous multiplication operations values of current to voltage with subsequent integration of the results of multiplication.

Known devices designed to verify electric meters, in which the metering of energy returned to the network exceeds the metering of consumed energy when the true values of the energy themselves circulating from the network and to the network through the metering device are equal [1-8].

The closest analogue (prototype) of the claimed technical solution can be considered a “Device for checking induction energy metering devices” [9], which contains storage capacitors charged with intermittent current at an increased interrupt frequency and continuously discharged back into the network, as well as transistor current interrupt and smooth switching circuits discharge of storage capacitors, characterized in that it includes two circuits connected in series from the series connected in series after being verified by the electric meter a capacitor and a bi-directional transistor switch, forming a bridge circuit so that the storage capacitor of the first circuit is connected to the phase conductor of the network, and the capacitor of the second circuit is connected to the neutral conductor of the network, and a triac and an inductor are connected in series to the diagonal of this bridge circuit, and the bi-directional transistors transistor switches of the indicated circuits and a triac connected to the corresponding outputs of the transistor and triac transistor, synchronization Started by which the network.

In addition, in this device, its transistor and triac control unit generates packets of high-frequency pulses for controlling the interruption of the charge current (recharge) of the capacitors in the first and third quarters of the mains voltage period when the triac is closed and transistors are closed in the second and fourth parts of the mains voltage period when the triac is opened with a small time delay of not more than 0.5 ms, relative to the beginning of the second and fourth quarters of the periods of the mains voltage.

The disadvantages of the known solution are its increased complexity associated with the need to form packs of high-frequency pulses supplied alternately to the pairs of transistors to provide an intermittent charge of the storage capacitors of the bridge circuit, the inability to use compact energy-intensive storage capacitors of the electrolytic type (monopolar) due to overcharging of such capacitors during operation of the device prototype for positive and negative half-periods of mains voltage and reduction ffektivnosti work back to the network during the entire quarter due to discharge storage capacitor (second and fourth) periods when the network voltage varies from an amplitude value (+/-) U to zero.

These disadvantages of the known solutions are eliminated in the inventive device.

The objectives of the invention are to simplify the design and increase its energy efficiency.

The set goals are achieved in a device for studying the operation of electric meters, the action of which is based on multiplying the instantaneous values of the mains voltage by the current in the active load, followed by integrating the results of these multiplications in time, containing a bridge circuit connected through a verified electric meter to the AC mains from two connected branches from series-connected storage capacitor and power transistor in series with the diagonals of the bridge circuit connected by a thyristor and an inductor (inductor), and in the first branch of the bridge circuit, a storage capacitor is connected to the phase conductor, and in the second branch - a power transistor, in addition, the device includes a control unit for power transistors and a thyristor, characterized in that used as storage unipolar compact and energy-intensive electrolytic capacitors, and rectangular pulses of opening the power transistors of the duration are formed in the power transistor and thyristor control unit (T / 4) -ΔT, where ΔT <T / 16, for each positive half-period of the mains voltage, as well as the triggering pulses of the thyristor, delayed in time from the times (T / 4) -ΔT in each positive half-period of the mains voltage to small Δt _REF = ΔT- (Δt _IMP / 2) << T / 16.

The achievement of the objectives of the invention is explained by the simplicity of the formation of control pulses for opening the power transistors of the bridge circuit, the use of electrolytic capacitors and the formation of discharge pulses of storage capacitors, centrally symmetric to the time T / 4 for each of the positive half-periods of the mains voltage, for which the voltage acting on the multiplier of the electric meter is maximum Moreover, significantly larger than the amplitude value U of the mains voltage due to consequently turning on the thyristor of two charged storage capacitors of the bridge circuit at time points (T / 4) -ΔT + Δt _REAR in each of the positive half-periods of the mains voltage, which significantly increases the counting of electricity by the counter in comparison with direct accounting of electricity. The thyristor is _opened with a small delay Δt _REF << ΔT after closing the power transistors, which eliminates the discharge of storage capacitors through power transistors.

In fig. 1 shows a diagram of the device, in Fig. 2 shows time diagrams, in fig. Figure 3 shows a block diagram of a power transistor and thyristor control unit, the capital letters of the Russian alphabet indicate the relationship of this unit with elements of a bridge circuit, and in fig. Figure 4 shows a fragment of the control unit — its phase-shifting circuit, which provides a phase shift of the mains voltage by an angle Δφ = ω [(T / 4) -ΔT].

In fig. 1 the following components are indicated:

1 - storage capacitor of the first circuit of the bridge circuit (capacity C),

2 - power transistor switch of the first circuit of the bridge circuit,

3 - power transistor switch of the second circuit of the bridge circuit,

4 - storage capacitor of the second circuit of the bridge circuit (capacity C),

5 - thyristor of the diagonal circuit of the bridge circuit,

6 - inductance coil (inductor) of the diagonal circuit of the bridge circuit (inductance L),

7 - control unit transistors and thyristor.

In fig. 2 shows time diagrams for positive half-periods of the mains voltage u (t) -Usinωt in the time interval 0≤t≤T / 2, charge current i (t) _{ZAR of the} storage capacitors 1 and 4 through open transistors 2 and 3 during the time interval (T / 4) -ΔT, as well as the current of their discharge back to the network i (t) _PIT during the time interval [(T / 2) -t _IMP ] / 2 + Δt _REF ≤t≤ [(T / 2) + t _IMP )] / 2. In the time interval of the discharge current of the series-connected storage capacitors 1 and 4 using an open thyristor 5, the voltage on the counter multiplier increases significantly to U + U _Δ , where ΔU <U, due to the inductance of the inductor 6, which reduces the discharge current and draws it into time to the magnitude t of the _IMF taking into account the effect of voltage resonance when the condition t _IMP = 2π (LC / 2) ^{1/2 is} fulfilled almost in the aperiodic mode due to the small figure of merit of such a resonant circuit (of the order of unity). When the discharge current is reduced to almost zero, the thyristor 5 automatically closes due to its known properties, and the discharge process stops. The resulting emf of reverse polarity in the inductor 6 when the thyristor 5 is closed is extinguished by the next positive half-cycle during the Tt time of the _IMP . The thyristor 5 must withstand a reverse voltage slightly larger than the double amplitude of the mains voltage 2U.

In fig. 3 is a block diagram of a power transistor and thyristor control unit. The block consists of the following elements and nodes:

8 - the first adjustable voltage divider network

9 - the second voltage divider network phase-shifting circuit,

10 - phase-shifting RC circuit connected to the second divider 9,

11 is a second adjustable divider phase-shifting RC circuit,

12 - the first comparator

13 - second comparator,

14 - the first inverter (circuit "NOT"),

15 - coincidence patterns ("I" patterns),

16 - second inverter (circuit "NOT"),

17 - element time delay on Δt _ZAD ,

18 - shaper short pulse starting the thyristor,

19 - pulse amplifier thyristor start,

20 - pulse transformer start thyristor, such as ferrite,

21 - pulse amplifier of duration (T / 4) -ΔT opening power transistors,

22 - pulse transformer of the amplifier 21, for example, on an iron core,

23 - resistors for limiting the current base of power transistors 2 and 3 and the control transition of the thyristor 5,

24 - grid capacitors in the base circuits of power transistors (for keeping power transistors closed in time intervals (T / 4) -ΔT≤t≤T).

In fig. Figure 4 shows a fragment of the control unit (Fig. 3), a phase-shifting circuit in which the mains voltage is reduced by a divider 9 from resistors R ₁ and R ₂ . In the first link R ₃ C ₁ , a phase shift of the reduced voltage supply is carried out with phase adjustment within 30 ° ≤Δφ ₁ ≤40 °, and in the second link R ₄ C ₂ - by Δφ ₂ = 45 ° with voltage level adjustment by the resistor R ₄ , Therefore, the total phase shift Δφ = Δφ ₁ + Δφ ₂ = ω [(T / 4) -ΔT] is adjustable from 75 ° to 85 °, thereby determining the discharge pulse width Δt _UTI .

Consider the action of the claimed device.

Let the phase shift Δφ = ω [(T / 4) -ΔT] by adjusting the resistor R ₃ (Fig. 4) determine the charging time of the storage capacitors 1 and 4 through open power transistors 2 and 3.

The voltage across the capacitors 1 and 4 when they are charged reaches the value U * <U equal to U * = sinω [(T / 4) -ΔT]> Usin (3ωT / 16). Given the small time delay Δt _REF << T / 16, the voltage U _Δ becomes slightly higher than the voltage U * and is close to the amplitude value of the network voltage U.

When thyristor 5 is turned on with non-conducting power transistors 2 and 3, the voltages at the storage capacitors add up and their voltage is 2U * ≈2Usin (3ωT / 16) = 1.848U. At U = 310 V, the voltage across the series-connected capacitors is U _∑ = 1.848 ∗ 310 = 573 V. This voltage has the same sign (positive) as the instantaneous values of the mains voltage in the range of the discharge time of the capacitors back to the mains. This means that the discharge current of the series-connected capacitors 1 and 4 will go in the opposite direction through the electric meter, and the voltage at the counter multiplying element will increase according to the quasi-harmonic law, taking into account the inductance of the inductor 6 to the value U + U _Δ <U _∑ = 573 V, for example to a value of about 500 V, that is, an average of 200 V more than the amplitude of the mains voltage at maximum at t = T / 4. The maximum value of the discharge current back to the network will naturally be determined by the internal resistance of the source and power line, including the overhead line (OHL) or underground cable and the input to the consumer from the OHL (cable). The uncertainty of this resistance value makes it impossible to accurately analyze the error of electricity metering by meters of various types (induction and digital).

However, it is clear that a strong inequality of the form is certainly observed:

, где напряжение u(t) в правой части неравенства учитывает прибавку с амплитудой, существенно большей, чем амплитуда U (например, с амплитудой U+U_Δ около 500 В). При этом очевидно, что отношение правой части указанного неравенства к его левой части будет существенно больше 1,18. Можно полагать, что применение данного устройства может наполовину снизить правильный учет потребляемой активной энергии (если указанное отношение интегралов принять равным 2) при относительной его простоте.

, where the voltage u (t) on the right-hand side of the inequality takes into account the increase with an amplitude significantly larger than the amplitude U (for example, with an amplitude U + U _{Δ of} about 500 V). It is obvious that the ratio of the right-hand side of the indicated inequality to its left-hand side will be significantly greater than 1.18. It can be assumed that the use of this device can halve the correct accounting of the consumed active energy (if the indicated ratio of the integrals is taken equal to 2) with its relative simplicity.

It should be noted that the use of this device in order to “rewind” the readings of electric meters by unscrupulous users leads to a certain increase in the voltage in the network, which must take into account the effect of such a distorted network on the quality of electrical appliances, such as refrigerators, televisions, computers and other electronic devices and devices, including AC motors (for example, in refrigerators).

The average power consumed by the bridge circuit with capacitors 1 and 4, for example, with a capacitance of C = 1000 μF, is P _ZAR = CU ² / T = 0.001 ∗ 310 ² / 0.02 = 4805 W. If we assume that the average discharge power P _PIT , TAKEN BY THE COUNTER during operation of the inventive device, turns out to be twice as large as the average charge power P _ZAR , then the average “unwind” power will be about 4.8 kW. When such a device operates for 6 hours a day (at night), “unwinding” in induction meters without a CO-2M backstop will amount to unaccounted for energy losses of 28.8 kW * hour / day. Price losses of the energy supplying organization per month at a rate of 4 r / kW * hour will amount to about 3,500 rubles. If consumers install electric meters with a backstop disc in induction meters or electronic meters, “rewinding” of the readings reduces to a slowdown in the rate of electricity metering when power consumption is more than 4.8 kW or to a complete stop of metering if the average power consumption is less than or equal to 4, 8 kW

The inductance of inductor 6 is calculated as L≈0.01T ² / 4π ² C, and for capacitors 1 and 4 C = 0.001 Φ we get L = 0.01 ∗ 0.0004 / 4 ∗ 9.86 ∗ 0.001≈0.0001 GN = 0.1 mH. The wave impedance of such a circuit is ρ = (L / C) ^1/2 = 0.32 Ohm, which indicates its low Q factor Q = ρ / r, where r is the active resistance of the inductor 6 and the power line.

Briefly consider the process of forming control pulses in the block in Fig. 3.

The comparator 12 generates positive rectangular pulses of duration T / 4 with a repetition frequency of the mains voltage F = ω / 2π. The comparator 13 generates the same pulses, but shifted in time by (T / 4) -ΔT. Using inverter 14, these pulses, while remaining positive, are shifted to the left along the time axis by half the period T / 2. Positive pulses following from the output of comparator 12 and inverter 14 are fed to the input of coincidence circuit 15, as a result of which a periodic sequence of positive pulses of duration (T / 4) -ΔT is formed at its output. These pulses are amplified in a pulse amplifier 21 with transformer separate output windings with grids on resistors 23 and electrolytic type capacitors 24 with a time constant of such grids about 15 ms, which allows holding a negative potential at the bases of power transistors 2 and 3 for a time T- (T / 4) + ΔT. The signal from the output of the matching circuit 15 also arrives at the second inverter 16 and then to the time delay element 17 at the Δt _ZAD , which can be a differentiating RC circuit. The positive pulses from the output of the differentiating circuit turn out to be tied to the decay of the pulses generated at the output of the coincidence circuit 15. The front of these pulses turns out to be slightly shifted from the pulse front at the output of element 16 by a small amount of delay Δt _ZAD , and it starts the short- _{circuit driver} 18, which starts the thyristor 5 , with a transformer output on a ferrite transformer 22. The delay Δt _{ZAD is} sufficient for reliable locking of power transistors 2 and 3 until the thyristor 5 is unlocked.

The device also includes a power supply for microchips and pulse signal amplifiers, not shown in the figures. This unit is powered by mains.

It should be noted that the recently advertised on the Internet device to reduce the readings of electricity meters by about 50% with a mass of 125 grams is nothing more than utter quackery and consumer fraud, which has nothing to do with science. The purpose of such advertising is to steal funds from buyers of this device. That is why the seller does not indicate his details, does not provide any technically understandable description and diagram of the device, relying only on the credulity of buyers and deceptive comments of many allegedly satisfied with the purchase of this product.

The inventive device is intended for developers of electric meters, the basis of which should not be based on the operation of multiplying the instantaneous voltage values by the current of the active load and integrating the results of such multiplication in time.

Literature

1. Smaller O.F. A device for checking the operation of single-phase induction electric meters, Patent No. 2474825, publ. in the bull. No 4 on 02/10/2013.

2. Smaller O.F. Bridge device for checking electric meters of active energy of induction type, Patent No. 2522706, publ. in No. 20 of 07/20/2014.

3. Smaller O.F. A method of compensating for losses at the end of a long power line. Patent No. 2512706, publ. No. 10 dated 04/10/2014.

4. Smaller O.F. The device voltaddavki electric network, Patent No. 2517203, publ. No. 15 dated 05/27/2014.

5. Smaller O.F. Device for monitoring electric meters, Patent No. 2521782, publ. No. 19 dated 07/10/2014.

6. Smaller O.F. Booster device for a three-phase power line, Patent No. 2515049, publ. No 13 on 05/10/2014.

7. Smaller O. F., System for stabilizing the voltage on an extended power line, Patent No. 2520311, publ. No. 17 dated 06/20/2014.

8. Smaller O.F. A device for studying the operation of induction electric meters, Patent No. 2523109, publ. in No. 20 of 07/20/2014.

9. Smaller O.F. A device for checking induction electricity meters, Patent No. 2521307, publ. No. 18 dated 06/27/14 (prototype).

Patent Search Data

RU 2338217 C1, 11/10/2008

RU 2181894 C1, 04/27/2002

RU 2190859 C2, 10/10/2002

RU 2178892 C2, 01.27.2002

SU 1781628 A1, 12/15/1992

SU 1780022 A1, 12/07/1992

SU 1422199 A1, 09/07/1988

US 7692421 B2 04/06/2010

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Claims (1)

A device for studying the operation of electric meters, the action of which is based on multiplying the instantaneous values of the network voltage by the current in the active load, followed by integrating the results of these multiplications in time, containing a bridge circuit connected through a verified electric meter to the AC network from two parallel branches connected from a series-connected storage capacitor and a power transistor with thyristor connected in series in the diagonals of the bridge circuit (simist ohm) and an inductor (inductor), and in the first branch of the bridge circuit, a storage capacitor is connected to the phase conductor, and in the second branch - a power transistor, in addition, the device includes a control unit for power transistors and a thyristor, characterized in that used as storage unipolar compact and energy-intensive electrolytic capacitors, and in the power transistor and thyristor control unit, rectangular pulses of opening power transistors of duration (T / 4) -ΔT are formed, where ΔТ <T / 16, for each positive half-period of the mains voltage, as well as the triggering pulses of the thyristor, delayed in time from time instants (T / 4) -ΔT in each positive half-period of the mains voltage by a small value Δt _REF = ΔT- (Δt _IMP / 2 ) << T / 16.

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