Device for compensation of reactive power

 

(57) Abstract:

Device for compensation of reactive power can be used on electric rolling composed of alternating current to improve the power factor of an electric locomotive that is a technical result. Device for reactive power compensation compensates reactive power with sinusoidal and non-sinusoidal shape of the supply voltage and current, as well as in various modes of operation of the locomotive by improving the shape of the input current, and the reactive component of the input current in modes different from the nominal. Device for reactive power compensation includes a load, a source of reactive power, consisting of series-connected inductance, capacitance, and two anti-parallel connected thyristors, the sensor network mode, which includes a voltage transformer and a current transformer, block sync pulses, and the load connected to the mains via the sensor network mode and parallel to the source of reactive power, the first sensor output mode network is connected to the input of the synchronizing pulses. What's new is that it gopalratnam, four-quadrant Converter, the DC voltage source, the control device is a key element, the first sensor output of the network mode is connected with the first inputs of the device computing the specified current and device management a key element, the second sensor output of the network mode is associated with the second input device evaluate a given current and the first input myCitadel, the output device evaluate a given current is connected with the second input myCitadel, the output of which is connected to the first input of the control unit four-quadrant Converter, a second input connected to the output of the synchronizing pulses, the DC voltage source via a four-quadrant Converter, whose input is coupled to the output control unit four-quadrant Converter, connected in parallel with the load, the second input device management a key element is connected parallel to the capacitor reactive power sources, and its output connected to the key element. Testing devices for reactive power compensation in electric VL showed a reduction of energy consumption by 5-7%. 1 Il.

The device relates to electrical engineering and prednaznache with thyristor converters.

One of the drawbacks of currently operating locomotives AC stepless voltage regulation (VL, VL) is a low power factor, reaching at best 0,84. The power factor is one of the major energy indicators of the locomotive, which defines the unproductive consumption of reactive power. The work of a locomotive with a low power factor leads to significant energy losses.

When non-sinusoidal shape of the voltage and current power factor Km locomotive is determined by the formula [1]

Km= cos (1)

where is the angle shift between current and voltage;

the distortion factor.

The last factor represents the degree of distortion of the input current and is determined by the ratio of the first harmonic current to its current value:

< / BR>
When calculating according to the formula (1) are taken into account higher harmonics, characteristic of non-sinusoidal currents and voltages. This ratio holds true for sinusoidal currents, since when =1 the expression (1) takes the form:

Km= cos (3)

Thus, the power factormcharacterized stepstool increase of active power and the simultaneous reduction of the jet.

To improve the power factor at the expense of cos apply compensating installation in the form of LC-circuits located on the locomotive and connected directly to the secondary winding it of traction transformer. The compensating device increases the power factor by creating a capacitive load and displacement of the primary current of the locomotive in the direction of advance of the supply voltage.

A device for controlling the compensated rectifier-inverter inverter electric rolling stock [2], which compensates for the reactive power consumed by the load with sinusoidal and non-sinusoidal supply voltage. Compensation is performed by connecting the secondary winding of the transformer locomotive inductive-capacitive LC compensator with fixed parameters of inductance and capacitance. When the inductive nature of the load that causes the capacitive current component that compensates the inductive component In this case, the phase of the input current is approaching the supply voltage, improving the power factor of a locomotive.

The device includes a voltage transformer load, LC-compens miraval switch-on pulses, the sensor voltage, the protection block, command block.

LC compensator through the key element is connected in parallel with the load and the secondary winding of the voltage transformer, the primary winding of which is connected to the network. The first input element And is connected with the sensor output voltage, the input of which is connected to the network. The protection unit is connected with the second input element And the output of which is connected to the input "R" trigger run. The inputs of the pulse shaper inclusion connected with the capacitor compensator and a secondary winding of the transformer, and the output - input "With" trigger start, the output of which through the pulse shaping key element is connected with the control input of the key element, the command block is connected to the input of a "D" trigger run.

The function of the key element is the inclusion of the compensator device. When this key element is designed in the form of two anti-parallel connected thyristors. Turning on the thyristor compensator is a signal from the trigger output is run through the pulse shaping key element. At enable input "With" trigger start signal from the output of the pulse shaper inclusion of armatura voltage. The signal at the output of the trigger start is generated after the filing of the input "D" of the signal of the command block. When this voltage appears at the output of the trigger coincides with the nearest point of equality of the voltages on the capacitor and the transformer.

The closing of the thyristors key element occurs or in case of exceeding the permissible stresses in the network, or when the protection operation. Signals for disabling are formed respectively by the sensor voltage and the protection block. In the presence of at least one of these signals at the input element And, at its output a signal applied to the input "R" to reset the trigger run This signal leads to the formation of the output trigger signal for the closing of the thyristors key element.

Thus, a key element in line with an-compensator permanently connected to the load, while the main purpose of controls is to prevent overcurrent possible when connecting an LC compensator to the voltage of the secondary winding of the transformer and provide fast-acting protection. Protection of the Converter is carried out by removing the control pulses to the thyristors in the event of a dangerous currents and voltages.

IP is the average value of the power factor of the locomotive is at the level of 0.92. With this increase the power factor of the locomotive is provided almost double the reduction in the consumption of reactive energy for traction of trains.

Thus, the use of LC-compensator of reactive power can significantly improve the power factor of the locomotive and to reduce energy losses by reducing the consumption of reactive power.

However, the application of LC-compensator with constant current compensation improves the power factor of the locomotive only under certain (nominal) load currents. The load deflection of the locomotive from the nominal causes incomplete compensation of reactive power, which reduces the efficiency of use of the device and the power factor is 0,82 - 0,85.

In addition, the amount of current compensation device is not affected by higher harmonic components of current and voltage circuit. It is known, however, that the magnitude of these harmonics determine the phase shift between the supply voltage and consumed by the locomotive shock. Therefore, these values should be considered when choosing the size of the current compensator.

It is also known a device for automatic regulation of reactive MOT opening angle of the thyristors is determined by the phase angle shift between the main harmonics of the network current and voltage. The current compensator is controlled so as to provide minimum phase shift between the input current and the mains voltage. This improves the power factor of an electric locomotive at different load currents.

Device for automatic control of reactive power includes a load, a source of reactive power, the sensor network mode, the block synchronizing pulses, a control unit and a unit pulse-phase control. The load uses a thyristor Converter. The source of reactive power consists of series-connected inductance, capacitance, and two anti-parallel connected thyristors.

The sensor network mode includes a voltage transformer and current transformer.

The load is connected to the mains supply through a current transformer and in parallel to the source of reactive power. The voltage transformer is connected in parallel to the mains supply, its output connected with the input clock, the output of which is connected with the first inputs of the control unit and the unit pulse-phase control. The output of the current transformer is connected with the second input of the control unit. The output of the control modules associated with the thyristors source of reactive power.

Reactive power compensation is due to the creation of the capacitive component of the load current conducted through the source of reactive power. The magnitude of this current is determined by the opening angle of the thyristors included in the source of reactive power.

The change of the load power factor is the magnitude of the phase angle shift between current and voltage of the supply network. This method of measurement is implemented using a sensor of reactive power, a control unit and a unit pulse-phase control. The output control unit is formed by a voltage proportional to the load power factor. With this voltage and pulse voltage sync input to the input unit pulse-phase control, converts the voltage into the phase control thyristors source of reactive power.

When reducing the power factor caused by the appearance of a phase angle shift between the grid current and voltage, the device automatically changes the opening phase of the thyristors. Changing the opening angle of the thyristors leads to an increase in the capacitive component of the current source reactive power flowing in thee between the supply voltage and the resulting load current, it leads to the improvement of load power factor. So is the compensation of the reactive power load in all modes of operation of the locomotive.

Thus, the known device can compensate for reactive power in all modes of operation of the locomotive.

However, the reactive power compensation device is possible only with sinusoidal voltage and current. This is because with sinusoidal voltage and current, the power factor is determined by the angle shift between these values. In this case, not considered of higher harmonic components of current and voltage. When distorted (non-sinusoidal) form of the supply current and voltage characteristic of the railroads alternating current, the power factor is defined as the ratio between active and total capacity consumed by the load. Therefore, the method of measuring the power factor adopted in the device, causing a measurement error with non-sinusoidal shape of the voltage and current, as active and full power also determine and higher harmonic components associated with the distortion of voltage and current. For this reason, the phase angle shift only between onok incomplete compensation of reactive power and poor energy performance of the locomotive, therefore, the power factor in this case is 0.85-0.88 to.

The basis of the invention is a device for compensation of reactive power, in which cos is increased as by improving the shape of the input current, and due to decompensation of a reactive component of the input current in various modes of operation of the locomotive.

The problem is solved in that the device for compensation of reactive power, containing will load, which is used thyristor Converter, a source of reactive power, consisting of series-connected inductance, capacitance, and two anti-parallel connected thyristors, the sensor network mode, which includes a voltage transformer and a current transformer, block sync pulses, and the load connected to the mains via the sensor network mode and parallel to the source of reactive power, the first sensor output mode network is connected to the input of the sync pulses, it introduced additional device evaluate a given current, myCitadel, the control unit four-quadrant Converter, four-quadrant Converter, DC, nadimi inputs of the device computing the specified current and device management a key element, the second output of sensor network mode associated with the second input device evaluate a given current and the first input myCitadel, the output device evaluate a given current is connected with the second input myCitadel, the output of which is connected to the first input of the control unit four-quadrant Converter, a second input connected to the output of the synchronizing pulses, the DC voltage source via a four-quadrant Converter, whose input is coupled to the output control unit four-quadrant Converter connected in parallel with the load, the second input device management a key element is connected parallel to the capacitor reactive power sources, and its outlet connected with key element.

Introduction in the device array of new elements (devices evaluate a given current, myCitadel, control unit, four-quadrant Converter, four-quadrant Converter, DC voltage and controls a key element) and their relationships allows us to influence the distortion factor of the current and cos (1,2). This is due to the approximation of the shape of the consumed current to a sine wave by suppressing the higher g is the input current, leading to the increase in cos differing from the nominal mode of operation.

One of the causes of reactive power is non-sinusoidal shape of the input current of the electric locomotive. Thanks to the four-quadrant Converter in the inventive device is creating an anti-phase higher harmonic currents generated by the four-quadrant Converter, and an approximation of the current locomotive sinusoidal shape due to the compensation of higher harmonics. Contrary to conventional wisdom, the suppression of higher harmonics contributing to the current approaches the sinusoidal form, in the inventive device leads to an increase in cos. Thus, the increase of the distortion factor reached as a result of improving the shape of the input current, changes its phase in the direction of approach to the supply voltage. This in turn increases cos locomotive and increases its power factor [5, Fig.30].

At the same time the presence of a four-quadrant Converter allows you to compensate for the reactive component of the input current and to increase cos in modes different from the nominal one.

Thus, cos in the unit of reactive power compensation increases due to both St is the nominal operating conditions. Due to this new way is an increase in the power factor of the locomotive TOM.

The drawing shows a diagram of an apparatus for reactive power compensation.

Device for compensation of reactive power contains the load 1, the source of reactive power 2, the sensor network mode 3, the block clock 4, the computing device specified current 5 myCitadel 6, the control unit four-quadrant Converter 7, the four-quadrant Converter 8, the constant voltage source 9, the control device is a key element 10. The source of reactive power 2 consists of series-connected inductance 11, tank 12 and two anti-parallel connected thyristors 13, 14. The sensor network mode 3 includes a voltage transformer 15 and the current transformer 16.

Load 1 is connected to the network through the current transformer 16 and a parallel circuit of series-connected inductance 11, tank 12 and the counter-parallel connected thyristors 13, 14. The voltage transformer 15 is connected in parallel with the grid, and its output connected to the input of block clock 4 and the first input device evaluate a given current 5 and is ycycline given current 5 and the first input vicites 6. The output of the calculation given current 5 is connected with the second input vicites 6, the output of which is connected to the first input of the control unit four-quadrant Converter 7, a second input connected to the output of clock 4. The constant voltage source 9 through a four-quadrant Converter 8, an input connected to the output of the control unit four-quadrant Converter 7 connected in parallel with the load 1. The second input of the control key element 10 is connected in parallel with the capacitor 12 reactive power sources 2, and its output is connected with the thyristors 13, 14 a key element.

As key elements of the four-quadrant Converter used power IGBT transistors, the device computing the set current and the control unit four-quadrant Converter is made on the basis of operational amplifiers and digital circuits, the average degree of integration, the block clock is made by a patent [6].

Device for reactive power compensation is as follows.

Using a chain of series-connected inductance 11 and a tank 12 that are configured on kazelektromash in nominal mode for it. In addition line with an-circuit suppresses the pulsation of the third harmonic of the input current, improving its shape. The thyristors 13, 14 and the control device is a key element 10 designed for on and off LC compensator with equal voltage across the capacitor 12 and the voltage measured at the output of the voltage transformer 15. Output voltage transformer 15 and the current 16 is formed by a voltage proportional to the instantaneous values of the supply voltage and supply current. Output device evaluate a given current 5 a signal is generated sine wave output whose value is determined by the active component of the input current. Using myCitadel 6 is determined by the difference signal is proportional to the distortion of the input current associated with higher harmonics and reactive component of the input current. The value of this signal the control unit four-quadrant Converter 7 generates a voltage control key elements of the four-quadrant Converter. For synchronous operation control unit four-quadrant Converter with the supply chain is a block clock 4. Due to the energy of the DC voltage source 9 at the output of alausa input current.

So is the compensation of the reactive component of the input current and the increase of cos as by improving the shape of the input current, and the reactive component of the input current in modes different from the nominal one.

Device for compensation of reactive power tested at the depot Belogorsk Transbaikalian railway. Experienced travel VL 65 showed a reduction of power consumption (5 to 7)%

Sources of information

1. L. A. Bessonov Theoretical foundations of electrical engineering. - M.: Higher school, 1984.

2. A. C. 1468791 Device to control the compensated rectifier-inverter inverter electric rolling stock. The inventors Century A. Kuchumov, C. A. Tatarnikov, N. N Sirotenko, H., Babaneuri. - Publ. in B. I. 12 1989 MCI 60 L 9/12.

3. N. N Sirotenko, C. A. Tatarnikov, H., Babaneuri. Improvement in energy AC locomotives. - Railroad transport, 1988, 7 S. 33.

4. A. C. 1674306. Device for automatic control of reactive power, the inventors A. C. Kopanev, B. M. Naumov. I. K. Yurchenko - Publ. in BI 32 1991 MCI N 02 J 3/18.

5. B. N. Tikhmenev. AC locomotives with statictest 2118038. The driver clock. Authors Y. M. Kulinich and centuries Kravchuk.

Device for compensation of reactive power, containing a load, a source of reactive power, consisting of series-connected inductance, a capacitor and a key element of the two anti-parallel connected thyristors, the sensor network mode, which includes a voltage transformer connected in parallel with the grid, and the current transformer, block sync pulses, and the load connected to the mains supply through a current transformer and in parallel with the source of reactive power, the output of the voltage transformer connected to the input of the sync pulses, characterized in that it additionally introduced device evaluate a given current, myCitadel, four-quadrant Converter, the control unit four-quadrant Converter, the DC voltage source, the control device is a key element, while the output of the voltage transformer connected to the first inputs of the device computing the specified current and device management a key element, the output of the current transformer is connected with the second input device evaluate a given t is El, the output of which is connected to the first input of the control unit four-quadrant Converter, a second input connected to the output of the synchronizing pulses, the DC voltage source via a four-quadrant Converter, whose input is coupled to the output control unit four-quadrant Converter connected in parallel with the load, the second input device management a key element connected to the capacitor reactive power sources, and its outlet connected with key element, and the output of the four-quadrant Converter generates a current, counter-current harmonics and reactive component of the input current and output devices evaluate a given current, a signal is generated sine wave, the value of which is determined by the active component of the input current.

 

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