SU875406A1 - Device for simulating short-circuiting current in distributed-parameter line - Google Patents

Description

The invention relates to electrical modeling and can be used in modeling systems having links with distributed parameters, in particular high voltage power lines. * A device is known for simulating currents in lines with distributed parameters on analog computers (AVMs) using either ¹ constant-delay ^10- volt units (BPZ), or they type on the AVM a circuit corresponding to the equivalent circuit diagram fl].

However, there is divergence neob- ¹⁵ to limit the number of elements of the equivalent circuit, and thus the frequency spectrum of a limit frequency. For a real range of g line lengths of 100-1000 km, for a set of ^{20 of the} corresponding number of elements of the circuit equivalent circuit, it is necessary to have 5-15 integrators, which, when using AVM MN-7M, corresponds to a modeling installation containing 1-3 AVM. Closest to the proposed technical essence is a device containing a sinusoidal function generator dialed to the AVM, the output of which is supplied through the voltage divider to one input of the adder, and the input of the constant delay unit, the output of which is connected through the second voltage divider to the second input of the adder [2 ],

However, when using commercially available constant delay units (BPZ-2M ^, based on the expansion of the delay function in a Pad series, errors arise due to the limited frequency characteristics of serial BPZ.

The purpose of the invention is to reduce the error of the device for modeling a short circuit current in a line with distributed parameters, i.e. increased accuracy.

This goal is achieved in that, in a device for simulating a short circuit current in a line with distributed parameters, containing a sinusoidal oscillator with outputs sinx, -sinx, cosxcosx and voltage dividers, the outputs of which are respectively connected to the inputs of the summing amplifier, the output of which is the output of the device , (In addition, a clock generator, a relay and a control unit containing a single-shot, the output of which is connected to the counter input, the outputs of which are respectively connected to the input decoder rows, each output of which through a series connection of the corresponding flip-flop and a key coupled to the control input of the respective switch, and outputs the sine wave generator through respective relay make contacts connected to respective inputs of the voltage dividers, clock generator output being connected to the input of the monostable control unit.

The drawing shows a diagram of a device.

The device comprises a sinusoidal oscillation generator 1 having four outputs that are connected to the inputs of the voltage dividers 2 through the contacts 3 of the relay 4, the windings of which are connected to the outputs of the control unit 5, consisting of a single-vibrator 6 connected in series, a counter 7, a decoder 8, a trigger 9, and keys 10, the input of which the output of the clock generator 11 is turned on. The outputs of the voltage dividers 2 are connected to the input of the summing amplifier 12.

The device operates as follows.

'B. In the initial state, the windings of all relays 4 are de-energized, all contacts 3 are open and there is no signal at the input of summing amplifier 12, it has zero output. When starting the AVM, the clock generator 11 closes the contact for a short time at the output of the counter 7, a signal appears corresponding to unity, while the potential appears at the first output of the decoder 8, the trigger of this output is activated, the key 10 is opened, and the current is supplied to the winding of the first relay. Are closed.contacts of this

Ζ.

At the time of the relay and at the input of the summing amplifier 12, two signals appear, selected so that there is a signal at its output. is equal to i (t) = sir »(Cil't + Ϋ) ₅ after a given time interval Δ t again.

The clock generator 11 closes the contact at the input of the control unit, the single vibrator 6 is activated, counter 7 changes the output signal, the decoder, trigger, key, relay are activated, the contacts of the second relay are closed. At the same time, at the input of the summing amplifier 12, two more sig ₁₅ signals appear, selected so that their sum is equal to

51 and (cH + <?) + <L ₂₂ co ₅ (wt + Ψ) - ⁹ ((¢ £ + _2 where οι, <^ 22. ” ^Coe Transmission factors ²⁴ at the corresponding inputs of the summing amplifier;

- amplitude EMF

- wave impedance of the line;

- the angular frequency of the forced component of the transient current;

- the initial phase of the EMF;

- time;

- travel time of the electromagnetic wave along the line.

time 2 Δ t the process occurs as described above, two more signals are connected to the input of the summing amplifier, etc. The playback time of the process is limited to ^{40 by the} number of outputs of the control circuit, to which relay windings can be switched on. With p-outputs, the total time of the reproduced process is t _D = (n-1) At ^s = (p-1) 2Г. ^R

Thus, the implementation of the VA devices in accordance with the invention allows to increase the accuracy of the transient simulation while reducing the cost and dimensions of the installation. , fifty

Claims (2)

154) A DEVICE FOR SHORT CIRCUITS FOR A SHORT CIRCUIT IN A LINE WITH DISTRIBUTED PARAMETERS 1 The invention relates to electrical modeling and can be used to model systems having links of distributed parameters, in particular high-voltage transmission lines. A device is known for simulating currents in lines with distributed parameters on analog output calculators (AVMs), using either the I constant time delay units (BPSs), or they are dialed into an AVM circuit corresponding to the chain replacement circuit l. However, it becomes necessary to limit the number of elements of the replacement circuit, and hence the frequency spectrum, to a certain limiting frequency. For a real range of lengths of 100–1000 km, it is necessary to have 5–15 integrators for recruiting the corresponding number of elements of a chain replacement circuit, which, when using the AVM MN-7M, corresponds to a simulation installation containing 1-3 AVMs. The closest to the proposed technical entity is a device containing a sinusoidal function generator, dialing AVM, the output of which through a voltage divider is fed to one input of the adder, and the input of a constant delay unit, the output of which is turned on through the second voltage divider to the second adder input f2}. However, when using commercially available constant delay blocks (BPZ-2M, based on the decomposition of the lag function in the Pad series, errors arise due to the limited frequency characteristics of the serial SCRs. The purpose of the invention is to reduce the error of the device for modeling short-circuit current in line with distributed parameters, i.e., an increase in accuracy. The goal is achieved by the fact that, in a device for simulating a short circuit current in a line with distributed parameters, a sinusoidal oscillator with outputs sinx, -sinx, cosxcosx and voltage dividers, the outputs of which are respectively connected to the inputs of a summing amplifier, whose output is a device output, additionally a clock frequency generator, a relay and a control unit containing a single-oscillator whose output connected to the input of the counter, the outputs of which are respectively connected to the inputs of the decoder, each output of which is connected to the control input corresponding to its relay, the outputs of the sinusoidal oscillator are connected via the closing contacts of the corresponding relays to the inputs of the corresponding voltage dividers, the output of the clock frequency generator is connected to the input of the one-oscillator of the control unit. The drawing shows a diagram of the device. The device contains a generator of 1 sinusoidal oscillations, which has four outputs that are connected to the inputs of voltage dividers 2 through the contacts 3 of relay 4, the windings of which are connected to the outputs of control unit 5, consisting of a series-connected single-oscillator 6, counter 7, decoder 8 , trigger 9 and keys 10, the input of which includes the generator output 11 clock frequency. The outputs of the voltage dividers 2 are connected to the input of the sum of the amplifier 12. The device operates as follows. B. The initial state of the winding of all relays 4 is de-energized, all contacts 3 are open and there is no signal at the input of summing amplifier 12, its output is zero. When the AVM is started up, the 1I so-frequency frequency generator is short-lived: on closing the contact at the output of counter 7, a signal appears. The corresponding unit in this case, the potential appears at the first output of the decoder 8, the trigger of this output is triggered, the key 10 is opened and current is supplied to the winding of the first relay. The contacts of this relay are closed and at the input of the summing amplifier} 2 two signals appear, selected so that its signal is at its output. equals l (t). sfn (OU-fc + y) at a predetermined time interval d t again, the clock frequency generator I1 closes the contact on the control unit input, triggers: single-oscillator 6, counter 7 changes the output signal, the decoder, the trigger, the key, the relay, the contacts are closed second re 1 le. At the same time, two more signals appear at the input of summing amplifier 12, which are selected so that their sum is equal to d siH () M, co5 (() (C t + 4 -2cyCA where, transmission coefficients for the corresponding inputs of summing amplifier; amplitude EMF, line impedance; angular frequency of the transient current component; initial phase; EMF; time; travel time of the electromagnetic wave along the line. At the time of 2 D t, the process proceeds as described above, connecting two more signals to the input of the summing amplifier, etc. Play time The process is limited by the number of control circuit outputs that can be switched on the relay coils. With n-outputs, the total time of the reproducible process is tp (nl) ut (n-1) 2G. transient while reducing the cost and dimensions of the installation., invention The device for simulating a short circuit current in a line with the first parameters, containing a sinusoidal oscillator with outputs Sinx, -Sinx, COSX, -CQSX, and voltage dividers, the outputs of which are respectively connected to the inputs of the summing amplifier, the output of which is the output of the device, are given by the fact that, in order to improve the simulation accuracy, a clock generator, a relay and the control unit containing a one-shot, the output of which is connected to the counter input, the outputs of which are respectively connected to the inputs of the decoder, feces; the output of which is connected to the control via successively connected trigger 1CIM input of the corresponding relay and the generator outputs 6 sinusoidal oscillations through the saheecaKHiQie contacts of the corresponding relays are connected to the inputs of the corresponding voltage dividers, the output of the clock frequency generator is connected to the control unit one-oscillator input. Sources of information received during the examination 1.I. Dolgmnov and others. Calculation of transient processes in electrical systems on a computer. M., Energie, 1968, p. 6 2. Podgorny E.V. and Khlebnikov S.D. Modeling and calculations of transient modes in relay protection circuits. N “, Energie, 1974, p 95 (prototype).