Method of control of series compensation device
(57) Abstract:Usage: in electrical engineering systems of power supply of consumers with sharply varying schedules. Essence: compare the frequency of the occurring and calculated resonance oscillations in a power supply system as a function of the amplitude of the resulting oscillations and difference frequencies compared change capacitance install longitudinal capacitive compensation, and when exceeding the estimated frequency of resonance oscillations increase the capacitance of the installation of series compensation, and when exceeding the frequency of the occurring vibrations reduce the capacitance of the device longitudinal compensation. 1 Il. The invention relates to electrical engineering, in particular to the transmission and distribution of electricity, alternating current, and can be used in systems of power supply of consumers with sharply varying schedules.Known adjustable mounting longitudinal capacitive compensation containing the partitioned condenser battery (KB), the capacitance of which varies depending on the voltage at its input, the current line and shift angle between them. Nedostatiuschie solution in which, depending on the sign and magnitude of the damping rate of the oscillations of the transition process shunted all KB installation of series compensation (CCP) or its separate sections. This solution allows you to selectively protect the KB from oscillatory phenomena.A significant drawback of this solution is not taking into account the frequency of the resonance point frequency response (this order) power supply system that does not allow you to actively suppress emerged oscillatory phenomena and to effectively use the capacity of KB.It is also known technical solution, which presents expressions for determination of singular points of this order of power supply system with the installation of series compensation, permitting comparison of the frequencies of the oscillations of the load current and possible subharmonic oscillations with the singular points of the frequency response. In essence it is closest to the proposed and adopted for the prototype.A significant disadvantage of the prototype is the lack of active management of the modes of oscillation suppression.The purpose of the invention is the stability of the electricity system and the efficiency of the condensate is ncacii by changing its resistance depending on the amplitude envelope of the resulting subharmonic oscillations, measure the frequency of the subharmonic oscillations occur, determine the estimated frequency and the steepness of the amplitude of the resonant oscillation by formulas
calc= , where
A = + + ,
B = , whereaboutangular frequency network;
to- capacitance install series compensation;
PC- capacitance installation of shunt compensation;
n- inductive load resistor;
with- inductive resistance in the food chain;
Fcalc= , where- the total inductive impedance;
R-total active resistance, determine the estimated difference emerged and resonant vibrations of providing the desired degree of resistance by the formula
calc= FBwhere is the required degree of stability, depending on the steepness of the amplitude of oscillations and the frequency difference between emerging and resonance oscillations,
FBthe amplitude of the arising of subharmonic oscillations, determine the new value of the estimated frequency of the resonant oscillations of providing the desired degree of resistance by the formula
calcl=calccalcdetermine resistancetolthat is relevant to the series compensation unit, equaltoland when exceeding the frequency of the resulting oscillation frequency of the resonant oscillations reducetoand when exceeding the estimated frequency of the oscillation frequency of the occurring oscillations increaseto.In the known technical solutions according to the results of the analysis of the decay constant envelope subharmonic oscillations of the transition process changes the resistance of the KB series compensation by shunting its individual sections. Such regulationtowithout taking into account the frequency characteristics of the electricity system in some cases may not lead to suppression, but to increase the oscillatory process, because the regulation is essentially "blind" and with decreasingtocan sometimes not be removed but rather to approach the resonant points in this order power system. In these cases, in the future it is necessary to shunt the entire KB series compensation, causing additional disturbance in the system, the violation of its stable operation.In this way, before you switch partitions KB determine in which direction the frequency fluctuations arisingINare resonance points this order - (calcand then Nero stability of power system . Thus the higher the amplitude of the resulting subharmonic oscillations FBand the steeper the amplitude of the resonance points this order Fcalcthe further apart in frequency response must be these points, i.e., the greater must be the value of calc. In the simplest case, this dependence can be taken linear (directly proportional), and in General is functional.The implementation of the method of regulation of the code of criminal procedure is illustrated using the installation shown in the drawing.Installation of series compensation consists of a series of n sections of the capacitor battery 11, 12, . . . , 1nn switching blocks 21, . . . , 2nunit 3 selection voltage on KB, bandpass filter 4, block 5 frequency oscillations, block 6 determine the amplitude, three analog-to-digital converters 7, 8, 9, computing device 10, the sensor 12 voltage, phase detector 13, block 14 for determining the resistance of the load, the control system 15.The device operates as follows.The deflection voltages KB allocated block 3 and is supplied to band-pass filter 4. The filter extracts envelope fluctuations naemul order is possible in this network with the CPC subharmonic resonance oscillations in KB, for example, from the third to the tenth. Next, the video signal from the bandpass filter 4 at the same time on the block for determining the oscillation frequency of 5 and an amplitude of oscillation 6, they are then converted from analog to digital form by analog-to-digital converters 7 and 8 and fed to the computing device 10.At the same time removed the signals proportional to the current line from the current sensor 11 and the output voltage of the CPC sensor voltage 12 which are fed to a phase detector 13, which determines the phase angle between them. The signal from phase detector 13 along with the signals from the current sensors 11 and voltage 12 is supplied to the block definition of the resistors 14, working on the algorithm:
(1) If necessary, to the fourth input of the unit resistors 14 may be filed with the signal from the device of reactive power compensation (shown dotted).Further, the signal from the unit 14 to determine the resistance of the load from an analog form is converted to digital form in analog-to-digital Converter 9, and is supplied to the computing device 10, which is a microcontroller in a single chip design, but can be performed on a separate e is em:
1. The resonance point frequency characteristics of the power supply system according to the expressions
P1= , where
A = + + ,
B = ,
(2) whereaboutangular frequency network;
to- capacitance installation of series compensation, the video signal from the system 15 controls the switching blocks of the CPC;
PC- capacitance device shunt compensation;
n- inductive load resistance, the video signal from the ADC 9;
with- inductive resistance in the food chain
Fcalc= , where- the total inductive impedance;
R- total active resistance.2. The estimated difference emerged and resonant vibrations of providing the desired degree of resistance by the formula
calc= FBwhere is the required degree of stability, depending on the steepness of the amplitude of oscillations and the frequency difference between emerging and resonant oscillations;
FBthe amplitude of the arising of subharmonic oscillations.3. The new value of the estimated frequency of the resonant oscillations of providing the desired degree of resistance by the formula
calcl=calccalc< / BR>4. lebani, and the necessary changes in the capacitance of the code of criminal procedure, and then checks the required degree of stability of the power system in the proposed discrete change of the resistance of the KB and the new values of the frequencies calculated resonance points.After performing these operations, the computing device 10 sends a signal to the input of the control system 15 of the switching blocks 2n, which generates a signal for switching the respective block 2i.Switching unit 2icarries out the necessary changes in the capacitance of the capacitor battery of the CPC. Thus, the device provides a necessary and sufficient switching sections KB installation of series compensation to ensure the required degree of stability of the power system, when this is entered or removed from the food chain, not the entire KB, and only certain sections, which ensures efficient use of the overall capacity of the capacitors.In the algorithm computing device 10 may be used and other expressions to determine the resonant frequencies of all points of the supply system with regard to inductive reactance of the source of disturbances, the economic components of the influence of the capacitance of the code of criminal procedure subtle, therefore, in this range of frequencies of perturbations it is advisable to implement a similar control of the capacitive resistance of the installation of shunt compensation.The algorithms determine the necessary change in the capacitance of the capacitor battery installations longitudinal and transverse compensation in the form of a program recorded in a persistent storage device of the computing device 10. The application of this method allows for more precise regulation of the resistance of the KB series compensation and flexible use of modern element base, all blocks of the device can be implemented on standard chips. METHOD of CONTROL of series COMPENSATION DEVICE, in which change their resistance depending on the amplitude envelope of the resulting subharmonic oscillations, characterized in that, in order to increase the stability of the power system and efficient use of capacitors to measure the frequency of the subharmonic oscillations occur, determine the estimated frequencycalcand the amplitude of the resonant oscillation by formulas
where A = + + ,
B = ,
whereoangular frequency;otulana installation of shunt compensation;
Xn- inductive load resistor;
Xwith- inductive resistance in the food chain;
where X- the total inductive impedance;
R- total active resistance, determine the estimated difference emerged and resonant vibrations of providing the desired degree of stability, according to the formula
where the required degree of resistance that depends on the amplitude of oscillations and the frequency difference between emerging and resonant oscillations;
F - amplitude occurred subharmonic oscillations,
determine the new value of the estimated frequency of the resonant oscillations of providing the desired degree of stability, according to the formula
determine the resistance of X corresponding to the new value of the estimated frequency of the resonant oscillation, set the capacitance of the installation of series compensation equal to X , and when exceeding the frequency of the resulting oscillation frequency of the resonant oscillations reduce X , while exceeding the estimated frequency of the oscillation frequency of the occurring vibrations - increment X .
FIELD: electrical engineering; energy storage, motor starting gear, ac networks.
SUBSTANCE: polarized capacitors or electrochemical batteries are used in standard ac circuits as polarized electrical charge storage devices with new circuit pattern. In one of alternatives opposing-series configuration of first and second polarized devices is used in ac network to improve its operating conditions. At least one dc power supply is provided to keep polarized devices shifted in forward direction when ac signal arrives at them. This ac signal is applied to devices connected in series opposition to excite ac load. These devices are sufficiently shifted by at least one dc voltage supply so that they remain displaced in forward direction upon connection to ac signal.
EFFECT: enhanced effectiveness and economic efficiency of polarized charge storage devices in all their applications.
64 cl, 32 dwg
FIELD: electrical engineering; correction of instant-power passive components associated with characteristics features of load.
SUBSTANCE: proposed corrector uses circuit arrangement of single-phase voltage inverter in the form of transistor bridge incorporating inverted diodes with storage capacitor connected across two diagonally opposite dc terminals and two diagonally opposite ac terminals connected through choke to supply mains in parallel with load; choke has sectionalized coil, that is it is made of two sections with output lead in-between; corrector is provided with newly introduced switch built around two thyristors and used to connect one section of choke coil during discharge of storage capacitor and both sections during its charge.
EFFECT: enlarged adjustment range of instant-power passive components; enhanced reliability of corrector.
1 cl, 2 dwg
FIELD: reactive power correction in three-phase loads.
SUBSTANCE: proposed reactive-power corrector has three-phase transformer, three single-phase inverters with control systems, rectifier, three single-phase current transformers, potential transformer, three single-phase reactive-current sensors, three voltage sensors, three comparison gates, and load; in addition it is provided with newly introduced unit of off-line voltage inverters, active and reactive power computing unit, active and reactive power ac component computing unit, desired current computing unit, off-line voltage inverter control unit, and current transformers of off-line voltage inverters.
EFFECT: enhanced mean power factor of enterprises, reduced maintenance charges.
1 cl, 1 dwg
FIELD: electrical engineering.
SUBSTANCE: proposed device tat can be used to raise efficiency of electrical energy consumption due to relieving power supply mains of reactive currents has three-phase diode bridge connected to supply mains through three reactors; connected at dc output of this diode bridge through isolating diodes are three storage capacitors. Device also has bridge inverter built around six transistors connected through their outputs to ac input of diode bridge and three additional transistors connecting dc input of inverter to storage capacitors. Transistor control system functions to convert signals arriving from outputs of voltage sensors across load, load and supply mains current sensors, and to generate thyristor control signals so that source automatically generates correction currents equal to reactive currents consumed by load, and only resistive component of load currents is consumed from supply mains.
EFFECT: reduced mass and size of device, ability of generating sine-wave corrective currents.
1 cl, 2 dwg
FIELD: electrical engineering; power factor correction for ac electric locomotive.
SUBSTANCE: reactive power correcting device has traction transformer, electric-locomotive rectifying converter with traction motor connected thereto, two reactive-power sources, supply-mains mode sensor, and switching unit; newly introduced are also two switching members, each incorporating thyristor switch, voltage sensor built around thyristors, and thyristor-switch control pulse shaper, as well as two resistors; thyristor switches are connected in series with first and second reactive power sources and resistors are connected in parallel with capacitors of respective reactive-power sources.
EFFECT: enhanced power factor due to improved waveform of output current and more complete correction of input-current reactive component under various operating conditions.
1 cl, 1 dwg
FIELD: power engineering; automatic tuning of capacitive current correction in network incorporating plunger-type arc-control reactor.
SUBSTANCE: proposed device for automatic tuning of adjustable-gap arc-control reactor correction has motor control unit connected to correction maladjustment recording unit and to control input of mentioned arc-control reactor provided with motor for air gap adjustment. Motor control unit has first contactor control unit connected through first auxiliary contact to correction maladjustment recording unit, second contactor control coil connected through second auxiliary contact to correction maladjustment recording unit, and third contactor control coil. First and second power contacts are connected to control input of adjustable-gap arc-control reactor; third and fourth auxiliary contacts are connected to short-pulse shaper. Final relay is connected to short-pulse shaper and its contact is inserted in third control coil of contactor. Fifth and sixth auxiliary contacts are connected in series with first contactor control coil and with second contactor control coil, respectively. Motor control unit also has rectifier bridge connected through limiting resistor and third power contact to control input of mentioned reactor incorporating air gap adjusting motor.
EFFECT: enhanced precision of reactor tuning in resonance with network capacitance.
1 cl, 2 dwg
FIELD: regulation and reactive power correction in power systems; inverters for high-voltage frequency-controlled electric drives.
SUBSTANCE: proposed converter is built around combined circuit arrangement incorporating three-phase bridge circuit of voltage inverter (with series-interconnected semiconductor devices of IGCT, IGBT, and other types) with one or more series-interconnected single-phase bridge voltage converters (whose semiconductor devices are not interconnected in series)connected to each of its phase outputs. All change-over operations are made in three-phase bridge circuit whose arms form valves with series-interconnected semiconductor devices and which forms output voltage base of converter at low frequency (such as that equal to supply mains frequency). Bridge arms incorporating series-interconnected semiconductor devices having different on/off delay times are changed over by means of switching circuits specially inserted in circuit.
EFFECT: enhanced reliability reduced power loss in building converter combined circuit, reduced dynamic loss in semiconductor devices.
3 cl, 9 dwg
FIELD: electric engineering, possible use for engineering of traction electric engines of electrically driven train.
SUBSTANCE: station for testing electric engines has transformer, controllable rectifier, inverter, engine, generator, first and second smoothing reactors, connecting shaft, voltage indicator, first and second current indicators, device for calculating input active current, first and second comparison element. Proportional-integral adjuster, pulse-duration modulator, autonomous voltage transformer and source of reactive power in form of a capacitor. Utilization of station for testing electric engines allows to increase value of power coefficient up to 0,994, and during testing of, for example, electric engine NB418 K6 of electrically driven train current consumed from network is decreased to 5-7 A.
EFFECT: increased energy coefficients due to increase of value of power coefficient by improving form of network current and approach of its phase to network voltage during substantial decrease of energy consumption.
FIELD: power engineering; reactive power correction.
SUBSTANCE: proposed method for controlling reactive power correction device incorporating thyristor-reactor group, higher-harmonic capacitor-bank filters, and reactive-power static condenser built around fully controllable diodes includes measurement of voltage U across ac buses, its comparison with Umax and Umin settings, generation of control signals, and generation of harmonics in static condenser current in phase opposition to current harmonics of thyristor-reactor group detected during analysis.
EFFECT: twice as low power of thyristor-reactor group, enhanced efficiency of input reactive power control and higher harmonic filtration.
1 cl, 1 dwg
FIELD: electric engineering, on railroad train of one-phased alternating current with zone-phased adjustment, acting as means for increasing power coefficient.
SUBSTANCE: reactive power compensator is connected in turns to one of several sections of secondary winding of traction transformer, powering appropriate shoulders of rectification-inversion transformer. Depending on value of reactive power of circuit, sections of reactive power source are connected to power source. Device for realization of proposed method for controlling reactive power compensator, additionally contains keys, which through reactive power compensator are connected to sections of secondary winding of traction transformer, keys control block, operation mode set-point device, indicators of voltage and current, calculating-measuring block.
EFFECT: compensation of reactive power, consumed by electric locomotive, and decreased electric energy consumption.