RU2428820C1 - METHOD BY MR KI GUTIN AND MR SA TSAGAREYSHVILI OF INPUT OF SIGNAL CURRENTS TO 0,4 kV THREE-PHASE POWER TRANSMISSION LINE AS PER "PHASE-EARTH" DIAGRAM WITH "PHASE-EARTH" POWER SOURCE - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: invention is intended to supply telecontrol signals from dispatch station (DS) installed at 35/10/0.4 kV substation to distributed controlled stations (CS) which are connected to 0.4 kV power transmission lines. Signals of remote indication of position of controlled switches and signals of remote measurements, which contain information on values of currents, voltages, cosφ, and readings of metres of electric energy of consumers, are transmitted from CS to DS.

EFFECT: reducing power losses.

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 signal currents into a three-phase electric network" patent RU 2224363. Bull. No. 5. This analogue has the following disadvantages:

1. The presence in the generator that implements the method of 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 taken as a 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 to a 0.4 kV three-phase power line according to the “Phase” - “Earth” circuit with the “Phase” - “Earth” power supply, according to which a circuit is passed current with a closed key : phase A, first inductor, input of a half-wave rectifier bridge, positive bus of a half-wave rectifier bridge, second inductor, key, negative bus of a half-wave rectifier bridge, another input of a half-wave rectifier bridge, wire "Earth", while accumulating electromagnetic energy W in the first inductor, characterized in that the key is closed in the time interval 0≤t≤0,14 T ₀ , at the time of opening the key due to the energy W excite free damped oscillations of the signal current i ₀ = I _m · cosω ₀ t · i ^-8t in the first resonant circuit, which is tuned to the frequency f ₀ in the circuit: phase A, first inductor, first capacitor, ground wire, create a second resonant circuit from the second inductor and the second capacitor, while in the 0.4 kV line get t the oxides of the direct - I ₁ and reverse - I ₂ sequences at a frequency of f ₀ , which are transformed into a 10 kV line, where they will be received by filters of the direct and reverse sequence, which are tuned to the frequency f ₀ , at the receiving point, where:

I _m - the amplitude of the signal current,

ω ₀ = 2πf ₀ is the angular frequency,

f ₀ - signal current frequency, 1

- период частоты тока сигнала,

- 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 first coil,

L ₄ - inductance of the first coil,

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

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

The result is achieved by introducing signal currents i ₀ into a three-phase 0.4 kV line using a resonant circuit, which consists of a coil 4, a capacitor 5, a ground wire and a low-voltage phase A, a transformer 10 / 0.4 kV, signal currents i _{0 is} transformed into a 10 kV line, and two currents are obtained: direct - I ₁ and reverse - I ₂ sequences, which are received at the receiving point by direct and reverse sequence filters that are tuned to the frequency f ₀ .

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. The first air inductor (coil), its inductance is equal to - L4;

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

6. Half-wave rectifier bridge;

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

8. The second coil, its inductance is equal to - L ⁸ ;

9. The third capacitor, its capacity is - C ₉ ;

10. Managed key (key);

11. The control unit;

12. The 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, bridge, is 17A, while the transformation coefficient of the air transformer is unity.

The power consumption in the prototype, subject to assumptions, is

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

R ₉ = 10 Ohm - the resistance of the resistor 9;

τ _CR = 0.25 T ₀ - the duration of the closed position of the key generator of the prototype.

- 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 τ _pr , when the key is closed, a coefficient of 0.25 is introduced in expression (1), since the key is closed for the time τ _pr = 0.25 T ₀ .

Initial data for the calculation of 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

Capacitors 5 and 7 are equal

The inductance of coils 4 and 8 is

The active resistance of coils 4 and 8 is

where Q = 10 is the quality factor of coils 4 and 8.

The total inductance of coils 4 and 8 is

The total resistance of coils 4 and 8 is

The claimed generator

The values of the inductance of coil 4 and the capacitance of capacitor 5 are selected from the resonance condition in the circuit loop: coil 4 - capacitor 5 - wire "Earth" at a frequency f ₀ = 1000 Hz with an open key, while neglecting the inductance of the windings and the transformer active resistances.

The values of the inductance of the coil 8 and the capacitance of the capacitor 7 are selected from the resonance condition in the oscillatory circuit with the key closed in the circuit: coil 8 - key - capacitor 7.

The capacitor 9 and the coil 8 are designed to create a resonant circuit in order to prevent the failure of the key 10 when it is opened due to the stored electromagnetic energy in the coil 8.

Define the capacitance of the capacitor 9 from the expression:

whence follows:

.

.

We determine the frequency of the current in the resonant circuit (L ₈ -C ₉ ), which decays exponentially

At time t ₁ , when the potential of phase A is greater than the potential of the Earth wire, then diodes 1 and 3 will be open, connect the generator to the 0.4 kV line. At the same time, capacitor 7 will start charging with current i ₁ along the circuit: phase A - coil 4 - first diode - "plus" capacitor 7 - "minus" capacitor 7 - third diode - 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 - first diode - coil 8 - the key is the third diode - the Earth wire. At the same time, the discharge current of capacitor 7 will flow along the circuit: “plus” capacitor 7 — coil 8 — key –– “minus” capacitor 7, and the charging current of capacitor 7 will flow through its charge circuit with 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), (7), (8), (9) and the adopted value τ = 0.14 T ₀ from the expression

; L_Σ=2,52·10^-3 Гн.where E ₀ = 310 B; R _Σ = 1.58 Ohms;

; L _Σ = 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 claimed 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, the amplitude of the current through the key at the time of its opening in the 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” - “Earth” circuit with the “Phase” - “Earth” power supply, according to which a circuit is passed with a closed key: phase A, first inductor , input of a half-wave rectifier bridge, positive bus of a half-wave rectifier bridge, second inductor, key, negative bus of a half-wave rectifier bridge, another input of a half-wave rectifier bridge, Earth wire, while electromagnets accumulate W hydrochloric energy in the first inductor, characterized in that the switch is closed in the free damped oscillation signal current time interval 0≤t≤0,14 T _0, a time key opening due to energy excite W i ₀ = I _m · cosωt · i- ^δt in the first resonant circuit, which is tuned to the frequency f ₀ along the circuit: phase A, first inductor, first capacitor, ground wire, create a second resonant circuit from the second inductor and second capacitor, while in line 0, 4 kV direct current obtained - I ₁ and the back - I ₂ successively Tei at a frequency f _0, which is transformed into the line 10 kV, which are received in filters direct and inverse sequences which are tuned to a frequency f ₀ in the receiving end, where I _m - amplitude of the signal current, ω ₀ = 2πf ₀ - angular frequency, f ₀ - signal current frequency,

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.