A way to automatically adjust arc reactor and a device for its implementation
(57) Abstract:The invention relates to the field of electrical engineering and is designed to automatically compensate for the capacitive current earth fault in networks 6-35 kV by the influence of the inductance arc reactor included in the neutral of the supply transformer. The technical result is to increase the accuracy of setting compensation and reliability of the electric grid. This technical result is achieved by the fact that in normal operation of the network is continuously monitored capacitance circuit zero sequence by typing in the neutral through the reactor source non-industrial and frequency measurement at this frequency, the corresponding current and voltage. When circuit inductance controlled arc reactor is tuned in resonance with the previously measured resistance circuit network using a closed-loop automatic control system by comparing the resistance with the current resistance of the reactor as a function of its current and voltage at industrial frequency. The method provides no resonance phenomena in normal mode when a high resistance R of the CSO channel automatic control, which monitors the current values of current, voltage and resistance of the reactor regardless of the non-linearity characteristics of the reactor and control system. 2 S. p. f-crystals, 1 Il. The invention relates to the field of electrical engineering and is intended for setting the compensation of the capacitive current earth fault in networks 6-35 kV by the influence of the inductance arc reactor (DR), included in the neutral of the supply transformer.Known methods extreme settings of compensation, in which either reaches a maximum natural or artificial bias voltage neutral during normal network operation, or use of the phase characteristics of the network, allocating a reference voltage and reducing to zero the angle between the selected voltage. First have insufficient sensitivity and low performance when you step reaching the point of resonance. In devices using phase characteristics, even when they are a significant complication of the introduction of the modulation reference signal, it is difficult to provide a residue accuracy, noise immunity and independence from natural bias neutral, the q of the circuit network and other settings.The closest quinny potential non-industrial frequencies and carry out resonant configuration according to the results of direct measurement of network capacity as a function of the current zero-sequence non-industrial frequency at constant corresponding EMF neutral. The method offers the versatility and reliability of measurement.The disadvantages of this method are the setting of this resonance in the resonance until the circuit that increases the value of the resonant overvoltages and reduces the reliability of the network, as well as the inability to apply the magnetically controlled reactors, which essentially have the ability to provide quick setting at the time of short-circuit to ground, thereby eliminating the loss of control and resonance phenomena in normal modes. In addition, when configuring podmagnichivaniem reactor in normal mode, this method does not eliminate the error associated with the nonlinearity of the current-voltage and adjusting the characteristics of such reactors.The purpose of the invention is to improve the accuracy of setting compensation and reliability of the electric grid.This goal is achieved by the fact that in normal operation of the network is continuously monitored capacitance circuit zero sequence by typing in the neutral through the reactor source non-industrial and frequency measurement at this frequency, the corresponding current and voltage, and in case of circuit inductance managed arcing is s automatic control by comparing the resistance with the current resistance of the reactor as a function of its current and voltage at industrial frequency.A simplified block diagram of a device that implements the proposed method, shown in the drawing and contains the following elements: input current transformers and voltage non-industrial frequency 1, the input current transformers and voltage of industrial frequency 2, a multiplier 3, a switch 4, a storage device 5, a proportional-integral (PI) controller 6, the system pulse-phase control (SETH) 7, the transducer bias current of the reactor 8, the non-industrial source frequency 9, which is a division of industrial frequency power supply 220 V three issues a frequency of 16.6 Hz, the bias controlled reactor with integrated additional windings and the current transformer 10, the supply transformer 11, in a neutral position which connects the reactor, and the standard voltage transformer ntmi or US 12, with the secondary winding of which is in the circuit device receives bias voltage neutral non-industrial and industrial frequency.The device operates as follows. In the normal mode, the source 9 is connected to the secondary winding of the reactor and on the input transducers 1 receives current and voltage frequency of 16.6 Hz. In the result of the division of voltage and current at the output of one of Umea configuration and capacity of the phases relative to the earth. When source circuit 9 is disconnected from the signal winding of the reactor, the last value of the capacitance of the circuit is memorized by the unit 5, and SETH served the resolution on the issuance of control pulses to the Converter.At the same time on SIFU 7 from the PI-controller 6 receives a control signal corresponding to the mismatch between the previously measured resistance network and the impedance of the reactor is obtained from the output of the other multiplier 3 by dividing supplied through the inverters 2 current values of voltage and current of the reactor at a frequency of 50 Hz. In the first time after closure of the load current of the reactor is close to zero, the maximum misalignment, and PI controller through SIFU fully opens the thyristors of the Converter 8, thereby providing a speedy exit of the reactor in a resonant mode. Upon reaching the desired value of the bias current and the resistance of the reactor to equal a fixed resistance capacitive circuit network, the error signal for the PI controller becomes zero, and further supported the resonance parameters settings before disappearance or eradication of personnel-phase circuit.Closing the DUT voltage on the reactor and its operating current, supported by a closed control loop in such a way as to keep the resonance tuning impedance. After removing the circuit and reducing the bias voltage neutral below the set point switch with time delay returns this to its original state for measuring the current values of the resistance circuit zero sequence network for the oscillator frequency of 16.6 Hz.Thus, the described device uses the method lies in the direct measurement of the most informative and reliable parameter - resistance of the reactor and its automatic regulation mode ground fault by comparing with the previously measured resistance of the circuit zero sequence. This method and apparatus have the following advantages.1. In normal modes by the absence of resonance overvoltages in power maximum detuning due to the high inductive resistance nepoznannogo reactor. At the same time quite accurately, reliably and easily (due to the presence in the reactor of the signal winding and ease of implementation of the generator frequency of 16.6 Hz) is monitored current value of the resistance of the circuit is zero, later the sensitivity of the measurements and eliminates the dependence of the amplitude of the signals from the deviation frequency, allowing broadband filters with low q.3. Modes of circuits to achieve high performance, precision and reliability due to the presence of the closed-loop system under direct parameters of the reactor. These are excluded as errors due to non-linear adjustment characteristics and error settings or deviations of the parameters of the elements of the control loop under the influence of temperature, aging, etc., (closed system provides output to the estimated value of direct comparisons).The implementation is provided in the standard equipment of measurement and control, both analog and digital. 1. A way to automatically adjust arc reactor included in the neutral of the supply transformer, which consists in creating a neutral artificial potential non-industrial frequency by introducing a neutral non-industrial source frequency, characterized in that the measured capacitance of the circuit on the non-industrial frequency, and when the single-phase earth fault remember capacitance of the circuit, turn off the non-industrial source frequency is in a previously fixed capacitance and the current resistance of the reactor, defined by the reactor current and the neutral voltage at the line frequency.2. The automatic tuning arc reactor for the implementation of the method according to p. 1, containing included in the neutral of the supply transformer arc reactor with two built additional windings and a current transformer, a source of non-industrial frequency, is connected to one of the secondary windings of the reactor through a switch connected to the voltage transformer, the secondary winding of which is supplied a bias voltage neutral, characterized in that it is equipped with automatic control to be included in the work under the regime of single-phase earth fault, consisting of two groups of input current transformers and voltage, is connected by its inputs to the transformers of current and voltage, and the outputs of the two multipliers, one output of which is connected to the input of a proportional-integral regulator, and the output of the second - to a storage device that is connected to its other input to the switch, and output to the second input of the proportional-integral controller, the output of which is connected to the input of the pulse-phase control, the output of which on
SUBSTANCE: ground short circuit detection device injects voltage with the frequency different from nominal between neutral point of synchronous three-phase electric machine and ground and measures resultant currents at two measurement points different from each other. Ground short circuit is determined on the basis of resultant current.
EFFECT: improving accuracy.
10 cl, 13 dwg
SUBSTANCE: device of protection against leakage currents comprises a unit of insulation monitoring and protective disconnection, a unit of detection and protective grounding of phase with damaged insulation, and also an additional unit of voltage comparison proportionate to voltage of neutral displacement sent from an additional AC winding placed in a compensating throttle with a reference one, and an additional relay impacted by this unit. Contacts of the additional relay are switched into the circuit of circuit breaker opening supplying voltage to the protected circuit, regardless of the position of contacts of the measurement relay of the unit of circuit insulation resistance monitoring, and into the circuit of relay winding control, providing for protective grounding of the grid phase with damaged insulation. In the unit of insulation monitoring and protective disconnection comprising a source of measurement current, a unit of its comparison with the reference one, a measurement relay, a unit to connect this source between phases of the protected circuit and earth is proposed to be made in the form of serially connected separating capacitor and compensating throttle, the AC winding of which is to be connected with zero point of secondary windings of the power transformer, and the contact of the measurement relay is to be connected into the circuit of breaker opening, through which the power transformer is supplied.
EFFECT: increased reliability and efficiency.
SUBSTANCE: source of DC measurement current is connected to grounding terminal through two parallel circuits; at that one circuit consists of the first additional resistor and normally closed contact of voltage relay connected in-series with the above resistor; the second circuit consists of the second additional resistor, diode connected in direction of measurement current passage and normally open contact of voltage relay connected in-series; alternating winding of compensatory choke is shunted by an additional capacitor. Out of two measurement circuits one is on when the other is off thus providing possibility to set setting for the device in each mode and to ensure required characteristics of the device in each mode; at that intrinsic safety of these circuits is ensured at voltage of measurement current equal to several hundred of Volts as it is required for protection devices in mains with voltage of 3 kV and more.
EFFECT: improving intrinsic safety.
SUBSTANCE: method consists in creation on a network neutral in its normal operating mode of an artificial potential from a generator of variable non-industrial frequency and measurement of parameters of the outline of zero network sequence based on the found frequency of resonance of fixed inductance of a reaction coil with the network capacity, and at occurrence of single-phase fault to ground - in recording of a measurement result, deactivation of the variable frequency generator and resonant adjustment of an arc-suppression reaction coil in compliance with the results of the last measurement, supplemented by the fact that as an arc-suppression reaction coil there used is a single-phase controlled reaction coil of a transformer type with short-circuit voltage of 100% between windings, and its resonant adjustment in the single-phase short-circuit mode in compliance with the earlier found values of capacitance current of the network is performed by selection of the required inductance resistance at outputs of secondary winding by means of a switchboard and a set of sufficient amount of resistances with values pro rata to the first numbers of ascending power series 2n, which can be connected to outputs of secondary winding of the reaction coil in series with possibility of shunting with the corresponding switch of the switchboard of any of them.
EFFECT: improving accuracy and quick action of adjustment of ASRC, including in modes of arcing short circuits, at simultaneous provision of harmonicity of compensation current.
SUBSTANCE: at earth fault protection of an electrical machine such as generator input signal with frequency fi is delivered to the electrical machine in order to generate periodic bias voltage at a busbar of the electrical machine. The response signal is assessed in order to identify closure. Frequency of the input signal is adapted, i.e. regulated or selected depending on a system parameter or system attribute of the electrical machine specific for the system noise interacting with the response signal and overlapping it. Thus selection of non-variable preset frequency of the introduced signal is rejected in favour of a flexible approach corresponding to the very last value of the electric machine parameter.
EFFECT: improving stability and reliability of the protection system.
12 cl, 3 dwg
FIELD: electrical and power engineering.
SUBSTANCE: proposed method intended for measuring current and voltage unbalance level and organizing on-line impact on them in three-phase power systems characterized in low quality of their power characteristics includes measurement of unbalance level with respect to reverse and zero sequence of both line and phase voltages and currents at frequency of each harmonic component. Frequency at which unbalance in analyzed characteristics occurs is found. Results obtained are used to generate control signal by correcting devices.
EFFECT: facilitated procedure.
1 cl, 5 dwg
FIELD: power engineering.
SUBSTANCE: method allows to fully utilize power of traction transformer due to loading its free phase by rectifiers and inverters, one of which is lead by leading phase of contact network, and second one of late phase, which allows to transfer electric energy to contact network, to exclude idling mode, to provide for lower asymmetry on reverse series in power grid 220 (110) kV, and also decreases level of higher harmonics.
EFFECT: higher efficiency, lowered values of quality coefficients of electric energy - asymmetry coefficient of reverse series and values of higher harmonics.
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: electric engineering, possible use in power circuits of various equipment.
SUBSTANCE: three-phased balancing device contains input and output clamps of powering networks. To output clamps, three-phased transformer is connected, primary windings of which are oppositely coupled in a zigzag. In accordance to the invention, between input and output clamps of powering network, first three-phased automatic switch is coupled, having an independent release. Serially with primary windings of three-phased transformer, second three-phased automatic switch is coupled. As zero contact for connection of phase loads, zero contact of primary windings of three-phased transformer, coupled oppositely in a zigzag, is used. Control block is connected serially to independent release, coupled between output clamp of one of the phases and zero contact of powering network, and ensures supply of voltage to independent release and activation of first automatic switch on disabling of second automatic switch.
EFFECT: increased reliability when powered from three-conductor or four-conductor powering network.
FIELD: electric engineering, possible use for powering various equipment.
SUBSTANCE: the balancing three-phased to one-phased transformer of alternating voltage contains input and output contacts, to which a transformer is connected which has primary windings in all three phases and two secondary windings in phases A and C. Primary windings are connected in a "zigzag". Windings of phases A and B, B and C, and also C and A are connected respectively. Secondary windings in phases A and C are coupled oppositely and are connected to output contacts.
EFFECT: reduction of stabilized power and asymmetry of primary currents and voltages.