RU2430467C1 - GUTIN'S AND TSAGAREISHVILI'S METHOD OF CURRENT SIGNAL INPUT IN 0,4 kV-THREE-PHASE POWER LINE IN "PHASE-PHASE" CIRCUIT WITH "PHASE-EARTH" POWER SUPPLY - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention serves to transmit telemetry signals from dispatcher station arranged at 35/10/0.4 kV-transformer station to dispersed controlled stations connected to 0.4 kV-power transmission line. Remote signaling signals on controlled switch states and are transmitted from controlled station to dispatcher station telemetering signals containing data on currents, voltages, cosφ, and consumer electric power meter readings.

EFFECT: reduced consumed power.

1 dwg

Description

The invention relates to the field of electrical engineering and is intended for transmitting telecontrol signals from a control room (DP) installed at a 35/10 / 0.4 kV substation to distributed control points (KP) that are connected to 0.4 kV power lines. From the CP to the DP transmit the signaling signals of the position of the controlled switches and the signals of television measurements, which contain information about the values of currents, voltages, cosφ, readings of electricity consumers' counters.

The well-known "Passive-active method of inputting currents of signals into a three-phase electrical network" (patent RU 2224363. Bull. No. 5). This ANALOGUE has the following disadvantages:

1. The presence in the generator that implements the method, an air transformer, in the manufacture of which it is difficult to obtain a coupling coefficient between its windings, close to unity, due to the large dimensions.

2. Large power consumption during the formation of current introduced into the line of 0.4 kV.

Also known is the “Method of Gutin K.I. input signal currents into a three-phase power line ”, which is adopted for PROTOTYPE (patent RU 2224365, H04B 3/54. Bull. No. 5, 2004), which has the same disadvantages as the analogue.

The objective of the invention is to reduce the power consumption of the generator compared to the PROTOTYPE without the use of an air transformer.

The technical result is achieved by the fact that in the method of inputting signal currents into a 0.4 kV three-phase power line according to the “Phase” - “Phase” scheme with the “Phase” - “Earth” power supply, in accordance with which a current is passed through the circuit with a closed key : phase A, first inductor, input of a half-wave rectifier bridge, positive bus of a half-wave rectifier bridge, key, negative bus of a half-wave rectifier bridge, another input of a half-wave rectifier bridge, ground wire, while this accumulates t W electromagnetic energy in the first inductor, characterized in that the switch is closed in the time interval 0≤t≤0,14 T _0, a time key opening due to the energy W, excite free damped oscillations of the current signal i ₀ = I _m · cosω ₀ t · i ^-8t in the first resonant circuit, which is tuned to the frequency f ₀ along the circuit: along the circuit: phase A, the first inductor, the first capacitor, phase B, while direct currents are obtained in the 0.4 kV line - I ₁ and the reverse - I ₂ sequences at a frequency f _0, which is transformed into the line 10 kV, which will be adopted f ltrami direct and inverse sequences, which are tuned to the frequency f ₀ in the reception section, wherein:

I _m - the amplitude of the signal current,

ω ₀ = 2πf ₀ is the angular frequency,

f ₀ - signal current frequency,

- период частоты тока сигнала,

- period of the signal current frequency,

i ^-8t is the attenuation coefficient of the current amplitude I _m ,

P _L4 is the active resistance of the first coil,

L ₄ - inductance of the first coil,

- энергия, которая была накоплена в катушке 4 в момент времени размыкания ключа.

- the energy that was accumulated in coil 4 at the time of opening the key.

The drawing shows a diagram of a generator that implements the claimed technical proposal, where:

1. Three-phase transformer 10/04 kV (transformer), which has a low-voltage phase A, B, C;

2. Three-phase power line 10 kV;

3. Three-phase power line 0.4 kV (0.4 kV line);

4. Air inductor (coil), its inductance is equal to - L ₄ ;

5. The first capacitor, its capacity is - C ₅ ;

6. Half-wave rectifier bridge;

7. The second capacitor, its capacity is - C ₇ ;

8. Managed key (key);

9. control unit;

10. Grounded neutral of the transformer 10 / 0.4 kV (wire "Earth"). We determine the power consumption by the prototype generator from the 0.4 kV line, while for simplicity of presentation, we neglect the active resistances and inductance of the windings of the air transformer. From the description of the prototype it follows that the amplitude of the current flowing along the circuit: bridge, primary winding of the air transformer, resistor, key, is 17 A, while the transformation coefficient of the air transformer is equal to one. The power consumption in the prototype, subject to assumptions, is:

where I _m = 17 A is the amplitude of the prototype current through the closed key at the time of its opening;

R ₉ = 10 Ohm - resistor resistance;

_straight 0,25T τ = ₀ - the duration of the closed position of the prototype key generator.

- период частоты f₀ прототипа.

- the period of frequency f _{0 of the} prototype.

Due to the fact that energy from the 0.4 kV network is consumed only in the time interval x _pr , when the key is closed, a coefficient of 0.25 is entered in expression (1), since the key is closed for a time τ _pr = 0.25T ₀ . Initial data for calculating the generator The frequency of the currents introduced into the 0.4 kV line is:

The power of the transformer that powers the generator is:

The capacitance of the capacitor 5 is equal to:

The inductance of coil 4 is equal to:

The active resistance of coil 4 is equal to:

where Q = 10 is the quality factor of the coil 4.

The claimed generator

The values of the inductance of coil 4 and the capacitance of capacitor 5 are selected from the condition of resonance of current i ₀ in the oscillatory circuit when the signal current i ₀ flows through the circuit: coil 4 - capacitor 5 - phase B - ground wire at a frequency f ₀ = 1000 Hz when open In this case, we neglect the inductance and active resistances of the transformer in connection with their smallness.

Define the capacitance of the capacitor 7 from the expression:

whence follows:

At time t _{1, we} connect the generator to the 0.4 kV line, when the phase A potential is greater than the Earth potential, then diodes 1 and 3 will open, and capacitor 7 will begin to charge with current i ₁ along the circuit: phase A - coil 4 - diode 1 - "plus" capacitor 7 - "minus" capacitor 7 - diode 3 - wire "Earth". The capacitor 7 will be charged to a voltage of E ₀ :

where E ₀ is the voltage amplitude of 220 V.

After charging the capacitor 7 to a voltage of E ₀ , the generator circuit will be in a stable state.

At time t ₂ > t ₁ , the key begins to commute with a frequency f ₀ when the key is closed for a time τ = 0.14 T ₀ , and a current will flow through it through the circuit: phase A - coil 4 - diode 1 - key - diode 3 - wire "Earth". At the same time, the discharge current of the capacitor 7 will flow along the circuit: the “plus” capacitor 7 is the key – diode 3 is the Earth wire, and the charging current of the capacitor 7 will flow along the charge circuit with the current i ₁ , while the charge current is equal to the discharge current, which are equal to each other and directed towards each other, maintaining the voltage across the plates of the capacitor 7 equal to E ₀ .

We determine the amplitude of the current through the key at the time of opening the key, taking into account (2), (5), (6), (9) and with the adopted value τ = 0.14T ₀ from the expression:

where E ₀ = 310 V; R ₄ = 1.58 ohms; τ = 0.14 T ₀ ; L ₄ = 2.52 · 10 ^-3 G.

Define the power loss from the network of 0.4 kV of the claimed generator by analogy with the expression (1):

Let us determine, taking into account (1), how many times the power consumption from the 0.4 kV network decreased when using the claimed generator:

Thus, the goal set by the invention is achieved, since the power consumption of the inventive generator from the 0.4 kV network is reduced by 12 times without the use of an air transformer. It should be noted that the power of the transformer 10 / 0.4 kV, the frequency of the currents f ₀ , the amplitude of the current I _m through the key at the time of its opening in PROTOTYPE and the claimed generator are taken equal to each other.

Claims (1)

The method of inputting signal currents to a 0.4 kV three-phase power line according to the “Phase” - “Phase” scheme with the “Phase” - “Earth” power supply, according to which a circuit is passed with a closed key: phase A, first inductor , the input of the half-wave rectifier bridge, the positive bus of the half-wave rectifier bridge, the key, the negative bus of the half-wave rectifier bridge, the other input of the half-wave rectifier bridge, the Earth wire, while the electromagnetic energy W is stored in the first coil in uktivnosti, characterized in that the switch is closed in the time interval ₀ 0≤t≤0,14T, when key opening time due to the energy W, excite free damped oscillations of the current signal i ₀ = I _m · cosω ₀ t · i ^-δt in the first resonant circuit that is tuned to the frequency f ₀ along the circuit: along the circuit: phase A, the first inductor, the first capacitor, phase B, while in the 0.4 kV line receive direct current - I ₁ and reverse - I ₂ sequences on frequency f ₀ , which transform into a line of 10 kV, where they are received by filters of direct and reverse sequence, cat The others are tuned to the frequency f ₀ at the receiving point, where I _m is the amplitude of the signal current, ω ₀ = 2πf ₀ is the angular frequency, f ₀ is the frequency of the signal current,

is the period of the signal current frequency, i ^-δt is the attenuation coefficient of the current amplitude I _m ,

, R _L4 is the active resistance of the coil, L ₄ is the inductance of the coil,

- the energy that was accumulated in the inductor at the time of opening the key.