Device filtering of harmonic currents and reactive power compensation in traction network 27.5 kv, 50 hz

 

(57) Abstract:

The invention relates to power supply systems for Railways. The technical result is to increase the filtering action of the device in relation to the higher harmonics of traction currents shoulder traction power substations and the reduction of active power losses in the shunt at a frequency of 50 Hz. For this purpose device filter higher harmonics traction loads, balancing and reactive power compensation allows you to filter the currents traction loads due to the introduction of active-capacitive shunt to the unit of reactive power compensation. In this case, the first harmonic energy losses in the shunt resistor is reduced by 4 times in comparison with the prototype, and filtering of harmonics increases in the 14-15 times compared with the device without compensation shunt and 3-4 times in comparison with the prototype. 1 C.p. f-crystals, 1 Il.

The invention relates to power supply systems for Railways, electrified with alternating current 27.5 kV, 50 Hz and can be used for effective filtration of higher harmonics traction currents on the side of 27.5 kV with simultaneous compensation of reactive power consumed by the traction AC. Device PR is the observance of standards on such indicators of quality of electric energy (SCE), as the coecients of the n-th harmonic component of voltage and distortion sinusoidal voltage curve at the points of common coupling (TOP) and simultaneous compensation of reactive power at a frequency of 50 Hz.

A device shunt compensation with the resonant reactor /1/, with custom batteries capacitors on the frequency 135-142 Hz and a device with a resonant reactor, and an active link filtering harmonics /2/.

Device /2/ the most close to the proposed device and it was taken as a prototype.

In the device /2/ capacitor Bank is divided into main and high-profile battery. Resonance battery included consistently to the core, is configured as a resonance voltage of the resonance reactor placed in series with it, at a frequency of 50 Hz.

Between the extreme conclusions of the resonant part of the battery and the reactor at a frequency of 50 Hz potential difference up to a setting equal to zero. Parallel to these findings connects the resistor with large resistance 80-100 Ohms to limit the losses of active energy at a frequency of 50 Hz. due to inaccurate settings of the reactor and the battery in the resonance voltage on this h is th shunt increases its shunting effect on the higher harmonics, but this action is not sufficient to bring the values of the coefficients of the n-th harmonic component of voltage and distortion sinusoidal voltage curve generated by the thrust of AC at the points of common connection, for valid values.

The technical result of the proposed devices is increasing its filtering action with respect to the higher harmonic traction currents shoulder traction power substations and the reduction of active power losses in the shunt at a frequency of 50 Hz

The essence of the claimed invention consists in that in the known device also includes a shunt battery, a switch and a resistor.

The drawing shows a diagram of the device.

All capacitor Bank is divided into main 1 and resonance 2 batteries. Resonance battery 2 is set in the resonance voltage of the resonance reactor 3 at a frequency of 50 Hz. The result is accurate to configure the voltage between pins 4 and 5, the potential difference at a frequency of 50 Hz is equal to zero. Parallel to pins 4 and 5 included a shunt circuit consisting of a switch shunting the battery 7 of the five capacitors type CAC-I, 05-63-U and resistor 8 of the resistance the hat 89,8 Ohms. Between the output 9 connecting the resonance reactor and a resonance battery and conclusion 10 connecting the resistor 8 and shunt the battery 7, the cutoff switch 11 and metalowy resistor 12, a resistance of 60 Ohms.

Scheme /2/ different from this scheme by the lack of items 7, 11 and 12. In /2/ resistor 8 is performed by a resistance of about 80 Ohms to limit the current frequency of 50 Hz, the current flowing through this circuit due to the mismatch of the resonance voltage frequency of 50 Hz between terminals 4 and 5. As a result, when the maximum error voltage between pins 4 and 5 525 (half the nominal voltage of one capacitor banks), the active power loss in the resistor 8 of the prototype at a frequency of 50 Hz are 3,45 kW and annual energy losses 30.2 thousand kWh (13 thousand rubles/year).

In the scheme of the invention is the inclusion in the shunt branch of the battery 7 can reduce the resistance of the resistor 8 to 20 Ohms, increasing at a frequency of 50 Hz resistance of this branch to 89.8 Ohms due to the capacitive resistance of the battery 7.

In the power loss in the resistor 8 is reduced to 0.68 kW and annual energy losses to 5990 kWh (2575 rubles/year).

The presence of capacitors in the battery 7 significantly limits the resistivity decreases to 35, 26, 236 Ohms, etc. that dramatically increases shunt the role of the device for higher harmonics current in comparison with the prototype.

The branch between nodes 9 and 10 are only required at the time of turning on or off and therefore the resistor 12 may be made on the basis of batala, i.e., from cheap material with a resistance of about 60 Ohms.

Diagram of the device when switching works as follows.

If all disabled elements turns on the switch 11, thereby shunting the resistors 12 and 8 resistance 60+20=80 Ohms resonant reactor. Then turns on the switch 13. Following this turns off the switch 11, and then turns on the switch 6, leaving always on shunt circuit consisting of a battery 7, a resistor 8. Remain enabled batteries 1, 2 and the resonant reactor 3. The device thus provides effective filtering of harmonics and reactive power compensation. Disconnect device is in the reverse order. Turns off the switch 6, the cutoff switch 11 turns off the switch 13.

Sources of information

1. K., Marquardt's. The supply of electrified Railways. M.: Transport, 1985.

2. AVT Is Pavlov, B. C. Shevtsov. BI 9, 1983 (prototype).

Device filtering of harmonic currents and reactive power compensation in traction network 27.5 kV, 50 Hz, with basic and resonance battery, a resonant reactor, a resistor, characterized in that it is equipped with a switch, the switch and the resistor is in parallel with the resonant battery and the reactor, and between the switch and the resistor is connected shunt capacitor Bank and between the output connecting the resonance reactor and a resonance battery, and the output connecting the resistor and shunt the battery, the switch and in series with him metalowy resistor.

 

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