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.
FIELD: electrical engineering.
SUBSTANCE: two engineering solutions are proposed which are characterized in common engineering goal and common approach to solution. Power supply has transformer incorporating primary windings 1, magnetic core 2, and secondary windings 3; connected in series with the latter is diode bridge 4 closed through poles to reactor coils 5 and 6. Novelty is that central lead of reactor coils 5 and 6 is connected to neutral of load 7. The latter is connected to supply mains through switch 8. Diode bridge with similar double-coil reactor is inserted in series with neutral of all three phases of three-phase load. Novelty in this alternative is that reactor center tap is connected to neutral of supply mains. Damping (smoothing down current peaks) is effected both when three-phase and single-phase loads are connected.
EFFECT: enlarged functional capabilities, ability of damping inrush load currents.
2 cl, 2 dwg
FIELD: computer-aided checkup of electrical energy characteristics.
SUBSTANCE: proposed method involves evaluation of coefficients of current and voltage sinusoid distortions, checkup of these characteristics for compliance with their rated values, and generation of control signal by devices correcting sinusoid of voltage and current levels. This method is characterized in that subharmonic and higher fractional components of current and voltage are included in evaluation of coefficient of current and voltage sinusoid distortions due to determination of actual period of voltage and current variations with time.
EFFECT: enhanced precision of checking voltage and current for their sinusoid distortions.
1 cl, 4 dwg
FIELD: railway transport.
SUBSTANCE: invention relates to longitudinal supply wire systems of non-traction consumers arranged near ac electrified railways. Proposed high-voltage wire system contains three-phase traction transformer connected with contact system and rail-earth and longitudinal power supply line connected with power consumer through electrical meter and consisting of two wires-phases under electromagnetic influence of contact system. Said line is additionally provided with third wire-phase grounded at substation and three-contact switch designed for simultaneously switching off three wires-phases at system supply cutoff mode. All three wires-phase are arranged on supports of contact system or on separately standing supports from field at equal distance from contact system. Electrical meter is made in form of three-element energy meter one element of which is connected to grounded wire-phase in direction of consumer. Use of proposed system reduces asymmetry of voltages at consumers and provides possibility of use of three-element energy meters and precludes emergency situations owing to no resonance conditions with no power losses for resonance.
EFFECT: increased economy of system.
FIELD: electrical engineering.
SUBSTANCE: proposed method intended to enhance power quality characteristics for users subject to negative influence of higher harmonic components includes generation of circuit current higher harmonic components which are in phase opposition to higher harmonics of supply mains using electrical energy of independent power supply.
EFFECT: enhanced electrical energy quality characteristics for power consumers.
1 cl, 3 dwg
FIELD: electrical engineering.
SUBSTANCE: proposed method used to enhance quality characteristics of electrical energy supplied to users susceptible to impact of negative factors of electrical-energy higher harmonic components includes generation of higher harmonic components of current in network which are acting in phase opposition relative to higher harmonics of supply mains.
EFFECT: enhanced quality characteristics of electrical energy supplied to users.
1 cl, 3 dwg
FIELD: reducing voltage ripples across power consumers incorporating rectifiers and inverters.
SUBSTANCE: proposed device has regulation channel, pulse source, series-connected voltage sensor, AC voltage component computing device, comparison gate, delta-modulator, and four-quadrant converter. Regulation channel has series-connected converter transformer, thyristor bridge, amplifier, and pulse distributor. Converter transformer input is connected to supply mains and pulse source output, to pulse distributor input. Voltage sensor input is connected in parallel with converter transformer primary winding and its output, to input of AC voltage component computing device and to second input of comparison gate; four-quadrant converter output is coupled with converter transformer secondary winding.
EFFECT: enhanced power output and mean time between failures.
1 cl, 3 dwg
SUBSTANCE: invention is attributed to electric engineering. For this purpose the device contains compensating block, control system, voltage sensing device and current transformer at that the compensating block includes device for alternating voltage component calculating, comparing element, delta modulator and self-commutated voltage inverter. Power unit consists of converter transformer, thyristor bridge and engine. Primary winding of voltage sensing device is connected between network and "ground", secondary winding of voltage sensing device is linked with input of alternating voltage component calculating device and the second input of compensating block comparing element. Primary winding of current transformer is connected between the network and primary winding of converter transformer, secondary winding of current transformer is linked with output of self-commutated voltage inverter of compensating block. Output of control system is connected with the second input of thyristor bridge.
EFFECT: providing maximisation of device operation stability, increase of electric locomotive power and increase of its travelling speed.
FIELD: power production.
SUBSTANCE: when non-sinusoidal shape of supply voltage is decreased, electric power is distributed between electronic devices distorting the shape of supply voltage and electronic devices improving the shape of supply voltage during the semi-wave of supply voltage. Device is connected in parallel with consumers introducing distortions of voltage shape. Main voltage is supplied to the device input. Device includes serial connection of phase-shifting chain, control pulse shaper, dc power supply and power switcher, which connects consumers improving the shape of supply voltage to the mains at a certain period of time.
EFFECT: improvement of supply voltage shape and simplification of device design.
2 cl, 4 dwg