RU2231849C1 - Frequency-difference relay - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention can be used as synchronization relay securing automation of process of switching on of synchronous generator. Frequency-difference relay incorporates meters of frequency and amplitude of network, two multipliers by constant coefficient, phase detector, low-pass filter, multiplier, three comparators, two actuators, meters of frequency and amplitude of generator, algebraic adder, inverter, divider, two AND gates, two formers of rectangular pulses, integrating amplifier, two pulse counters, two delay elements, storage register, clock pulse generator, former of sequence of short pulses. Meters of frequency of input and synchronized signals convert input and synchronized signals in compliance with mathematical expressions: U₀=A₀/f₀, U₁=A₁/f₁, where U₀ is signal across output of network voltage frequency meter; U₁ is signal across output of generator voltage frequency meter; f₀ is network voltage frequency; f₁ is generator voltage frequency; A₀,A₁ are scale coefficients proportional to amplitudes of voltages of network and generator. Meters of amplitude of network voltage and of generator voltage convert voltages of network and generator to values proportional to their amplitudes and equal to A₀ and A₁ correspondingly.

EFFECT: widened functional potential and enhanced precision of relay.

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Description

The invention relates to electrical engineering and can be used as a synchronization relay, providing automation of the process of switching on a synchronous generator.

A device is known that contains a series-connected clock generator, a binary counter, a decoder, a pulse shaper and an actuator made in the form of a transistor [1].

The disadvantage of this device is the relatively narrow functionality that does not allow using it as a relay of the frequency difference.

Closest to the technical nature of the proposed device is a device containing the first and second rectifier blocks that perform the functions of a voltage amplitude meter, made in the form of diodes, the cathode and anode of which are, respectively, the generator voltage terminal and the network voltage terminal, algebraic adder, the first and second the inputs of which are connected, respectively, with the anode of the first and the cathode of the second diodes, the first and second operational amplifiers, which are, respectively, an inverter and a comparator, inputs which are connected to the output of the algebraic adder, the third and fourth diodes, the anodes of which are connected to the outputs of the first and second operational amplifiers, respectively, a multiplier, the inputs of which are connected to the cathodes of the third and fourth diodes, the first and second inverters, the inputs of which are connected, respectively, to the cathodes the third and fourth diodes, and the first and second actuators, the inputs of which are connected, respectively, with the output of the first and second operational amplifiers [2].

The disadvantage of the closest technical solution is the relatively narrow functionality, since it generates a signal of approximate equality of the voltage amplitude of the network and the generator, which indicates the time interval of the possible adjustment of the generator frequency to the network frequency, but does not produce signals of unacceptable frequency mismatch between the input and synchronized signals at a given relative the permissible value of their mismatch, and also does not form an advancing signal used to accurately for prison generator to the network.

The technical result of the invention is the expansion of functionality and increased accuracy.

This technical result is achieved by the fact that in the device containing the generator voltage amplitude meter, the input of which is the generator voltage input, an algebraic adder, the first constant factor multiplier, an inverter, the first comparator and the first and second actuating elements, a network voltage frequency meter is input, an input which is the input of the mains voltage, and the output is connected to the input of the first multiplier by a constant coefficient and to the addition input of the algebraic adder, a frequency meter s of the voltage of the generator, the input of which is connected to the input of the generator of the voltage amplitude of the generator, and the output to the input of the divisible division unit, the input of the divider of which is connected to the output of the meter of the voltage amplitude of the generator, the multiplier whose output is connected to the subtracting input of the algebraic adder, and the first input to the output of the division unit, the voltage amplitude meter, the input of which is connected to the input of the network voltage frequency meter, and the output is connected to the second input of the multiplier, the second comparator, the first input which is connected to the first input of the first comparator and to the output of the algebraic adder, the second input of the second comparator is connected to the output of the inverter, the input of which is connected to the second input of the first comparator and to the output of the first multiplier by a constant coefficient, and the output “less” of the second comparator is connected to the input of the second an actuator connected in series to the first square-wave driver, the input of which is connected to the generator voltage input, and the sequence driver is short x pulses, the output of which is connected to the first input of the phase detector, the second rectangular pulse shaper, the input of which is connected to the input of the mains voltage, and the integrating amplifier, the output of which is connected to the second input of the phase detector, the third comparator, the low-pass filter, the input of which is connected with the output of the phase detector, and the output is connected to the input of the third comparator, made in the form of a comparator with a zero threshold, the first element And, the first and second inputs of which are connected to the ode is “less” than the first comparator and with the output “more” of the second comparator, respectively, a clock generator whose output is connected to the first input of the second element And, the second input of which is connected to the output “more” of the third comparator, and the third input is connected to the output the first element And, the first and second delay elements, the inputs of which are connected to the output “equals” the third comparator, the first pulse counter is connected in series, the counting input of which is connected to the output of the second element And, and the input is set and to zero - with the output of the first delay element, a memory register, the control input of which is connected to the “equal” output of the third comparator, and a second constant factor multiplier, as well as a second pulse counter, the counting input of which is connected to the output of the second element And, the feed input The initial setup code is connected to the output of the second multiplier by a constant coefficient, the control input of the second counter is connected to the output of the second delay element, the setup input to zero - with the output “equal” to the third comparator, and the output The second pulse counter is the output of the synchronization relay, and the constant coefficient generating unit, the input of which is connected to the output of the memory register and the output is connected to the input of the constant coefficient supply of the second multiplier by a constant coefficient, while the output “greater” of the first comparator is connected to the input of the first actuating element, frequency meters of the input and synchronized signals convert the input and synchronized signals in accordance with mathematical expressions

U ₀ = A ₀ / f ₀ , U ₁ = A ₁ / f ₁ ,

where U ₀ is the signal at the output of the network voltage frequency meter,

U ₁ - signal at the output of the frequency meter of the voltage of the generator,

f ₀ is the frequency of the mains voltage,

f ₁ - generator voltage frequency,

And ₀ , And ₁ - scale factors proportional to the amplitudes of the mains voltage and the voltage of the generator, respectively,

and the meters of the amplitude of the mains voltage and the voltage of the generator convert the mains voltage and the voltage of the generator into values proportional to their amplitudes and equal to A ₀ and A _1, respectively.

Figure 1 presents the electrical structural diagram of a synchronization relay, figure 2 - frequency meter, figure 3 is a timing diagram explaining the operation of the relay.

The synchronization relay (Fig. 1) contains a generator 1 of the voltage amplitude of the generator, the input of which is the generator voltage input, an algebraic adder 2, a first constant factor multiplier 3, an inverter 4, a first comparator 5 and a first 6 and a second 7 actuator, a frequency meter 8 mains voltage, the input of which is the mains voltage input, and the output is connected to the input of the first multiplier 3 by a constant coefficient and to the addition input of the algebraic adder 2. The relay consists of series-connected measurement a voltage frequency generator 9, the input of which is connected to the input of the generator voltage amplitude meter 1, a division unit 10, the input of which divider is connected to the output of the generator voltage amplitude meter 1, and a multiplier 11, the output of which is connected to the subtraction input of the algebraic adder 2, amplitude meter 12 network voltage, the input of which is connected to the input of the meter 8 of the frequency of the network voltage, and the output is connected to the second input of the multiplier 11, the second comparator 13, the first input of which is connected to the first input of the first comparator 5 and with the output of the algebraic adder 2. The second input of the second comparator 13 is connected to the output of the inverter 4, the input of which is connected to the second input of the first comparator 5 and with the output of the first multiplier 3 by a constant coefficient. The output “less” of the second comparator 13 is connected to the input of the second actuating element 7. The device also contains serially connected the first square-wave pulse shaper 14, the input of which is connected to the generator voltage input, and the short-pulse train former 15, the output of which is connected to the first input of the phase detector 16 , in addition, the second square-wave pulse generator 17, the input of which is connected to the mains voltage input, and the integrating amplifier 18, out, are connected in series One of which is connected to the second input of the phase detector 16. The device also contains a third comparator 19, a low-pass filter 20, the input of which is connected to the output of the phase detector 16, and the output is connected to the input of the third comparator 19, made in the form of a comparator with a zero threshold, the first element And 21, the first and second inputs of which are connected to the output “less” of the first comparator 5 and to the output “more” of the second comparator 13, respectively, the clock generator 22, the output of which is connected to the first input of the second element And 23, the second input of which is connected to the output “greater than” the third comparator 19, and the third input is connected to the output of the first element And 21, the first 24 and second 25 delay elements, the inputs of which are connected to the output “equal” of the third comparator 19, in series with the first pulse counter 26 , the counting input of which is connected to the output of the second element And 23, and the input of the installation to zero - with the output of the first delay element 24, a memory register 27, the control input of which is connected to the output “is equal” to the third comparator 19, and the second multiplier 28 is constant the coefficient, as well as the second 29 pulse counter, the counting input of which is connected to the output of the second element And 23, the input input of the initial setting code is connected to the output of the second multiplier 28 by a constant coefficient, the control input is connected to the output of the second delay element 25, and the installation input to zero - with the output “equals” the third comparator 19, and the overflow output of the second pulse counter 29 is the output of the synchronization relay, and the constant coefficient generating unit 30, the input of which is connected to the output of the memory register 27, and in turn connected to the input of the DC coefficient of the second multiplier 28 by a constant coefficient, the output of the "more" of the first comparator 5 is connected to the input of the first actuator, frequency meters and synchronized input signal and convert the input signals are clocked in accordance with mathematical expressions

U ₀ = A ₀ / f ₀ , U ₁ = A ₁ / f ₁ ,

where U ₀ is the signal at the output of the network voltage frequency meter,

U ₁ - signal at the output of the frequency meter of the voltage of the generator,

f ₀ is the frequency of the mains voltage,

f ₁ - generator voltage frequency,

A ₀ , A ₁ - scale factors proportional to the amplitudes of the mains voltage and the voltage of the generator, respectively,

and the meter 12 of the amplitude of the mains voltage and the meter 1 of the voltage of the generator convert the mains voltage and the voltage of the generator into values proportional to their amplitudes and equal to A ₀ and A ₁ , respectively.

The frequency meters 8 and 9 (Fig. 2) can be made in the form of an amplifier 31, in the output circuit of which a resonant circuit 32 is included, configured so that the nominal values of the input frequencies come in the middle of the linear part of the branch (decay) of its frequency response. In this case, the output voltage of the meter will be inversely proportional to the frequency of its input signal.

Figure 3 presents: a signal Uin14 at the input of the first rectangular pulse shaper 14 (Fig.2, a), a signal Uin17 at the input of the second rectangular pulse shaper 17 (Fig.2, b), a signal U14 at the output of the first rectangular pulse shaper 14 ( figure 2, c), the signal U17 at the output of the second rectangular pulse shaper 17 (figure 2, d), the signal U15 at the output of the shaper 15 of the sequence of short pulses (figure 2, e), the signal U18 at the output of the integrating amplifier 18 (figure .2, f), the signal U16 at the output of the phase detector 16 (Fig.2, g), the signal U19 at the output “is third comparator 19 (Figure 2, s), U29 signal at the output of the second counter 29 (2, s).

The synchronization relay operates as follows.

When the relay is turned on, a signal U ₀ = A ₀ / f ₀ is generated at the output of meter 8, the value of which is inversely proportional to the frequency f _{0 of the} mains voltage, and at the output of meter 9, a signal U ₁ = A ₁ / f ₁ is inversely proportional to the frequency f _{1 of the} voltage generator. At the same time, the meter 12 generates a signal proportional to A ₀ , and the comparator 13 generates a signal proportional to A ₁ . In this case, at the output of the algebraic adder 2, a relative frequency difference A ₀ / f ₀ -A ₁ A ₀ / A ₁ / f ₁ = A ₀ (f ₁ -f ₀ ) / f ₀ · f ₁ = A ₀ (f ₁ -f ₀ ) / f $\genfrac{}{}{0ex}{}{\text{2}}{\text{0}}$ because f ₁ = f ₀ .

In addition, the signal from the output of the meter 8 is multiplied in the first multiplier 3 by a small coefficient K, which determines the permissible deviation of the frequency of the synchronized signal from the input. Then, in the first comparator 5, the quantities A ₀ (f ₁ −f ₀ ) / f are compared $\genfrac{}{}{0ex}{}{\text{2}}{\text{0}}$ and A ₀ K / f ₀ , and in the second comparator 13, the quantities A ₀ (f ₁ -f ₀ ) / f are compared $\genfrac{}{}{0ex}{}{\text{2}}{\text{0}}$ and - A ₀ K / f ₀ , since its input receives the signal inverted by inverter 4 from the output of the first multiplier 3.

The first actuator 6 will work when the frequency of the generator voltage f ₁ exceeds the allowable deviation from the frequency of the mains voltage f ₀ upward by a relative amount specified by the coefficient K, and the second actuator 7 when the frequency of the voltage of the generator is unacceptably deviated downward.

The signal of the logical unit at the output of the first element And 21, corresponding to the resolution of the formation of the command to connect the generator to the network, will be observed when the generator frequency is within acceptable limits relative to the deviation from the network voltage frequency.

The connection command itself, which should be generated with a given lead time top, is formed as follows. The signal of a logical unit from the output of the first element And 21 goes to the input of the second element And 23, to one of the other inputs of which counting pulses for the first counter 26 come from the output of the clock generator 22. At the output of the phase detector 16, a constant voltage signal is formed, the amplitude of which is proportional to the angle between the voltage vectors of the generator and the network (Fig. 2, g). This signal after filtering in the low-pass filter 20 is compared in the third comparator 19 with a zero level, therefore, pulses will be generated at its output “equal to” (Fig. 2, h) at the end of each period of signal changes at the output of the phase detector 16. Between these pulses at the output “greater” than the third comparator 19, a logical unit level will be observed at which the pulses of the generator 22 will be supplied to the counting input of the first counter 26, in which a signal will be generated proportional to the period T of the output signal at the output e of the phase detector 16. At the same time, the same pulses are fed to the counting input of the second counter 29. By the signal from the output “is equal” to the third comparator 19, the contents of the first counter 26 (T value) will be transferred to the memory register 27, after which the contents of the first counter 26 will be reset . The contents of register 27 are multiplied in the second multiplier 28 by the number of Kop, the value of which is determined in block 30, made, for example, in the form of a ROM, based on a predetermined lead time top for turning on the generator in the network. Block 30 is programmed to calculate Cope based on the following equation: Cope = (1-to / T). In this case, the pulse from the output “is equal” to the third comparator 19 resets the contents of the second counter 29, after which the multiplication result is entered into this counter as its initial setting. When the counted number of pulses in the second counter 29 is equal to the duration of the time interval within the period of the signal changes at the output of the phase detector 16, a short overflow pulse is generated at the output of the second counter 29, which is used as a generator start pulse ahead of the value of to _.

Thus, the proposed device has wider functionality and higher accuracy, since it generates a signal to turn on the generator only in the interval corresponding to the permissible value of the mismatch of the frequencies of the voltage of the network and the generator, the determination of which ensures a low level of influence of the instability of their amplitudes.

Sources of information taken into account

[1] Electrical reference book, in 4 volumes, v.2. Electrical products and devices. / Under the general ed. V.G. Gerasimova et al. - M.: Publishing House MPEI, 1998, p. 390, Fig. 35.10.

[2] Andreev V.A. Relay protection and automation of power supply systems. M .: Higher school, 1991, p. 355, fig. 12.16.

Claims (1)

A synchronization relay comprising a generator voltage amplitude meter, the input of which is the generator voltage input, an algebraic adder, a first constant factor multiplier, an inverter, a first comparator and first and second actuators, characterized in that a network voltage frequency meter is introduced, the input of which is an input network voltage, and the output is connected to the input of the first multiplier by a constant coefficient and to the addition input of the algebraic adder, the generator measures the frequency of the voltage Ora, whose input is connected to the input of the generator voltage amplitude meter, and the output - to the input of the divisible division unit, the input of which divider is connected to the output of the generator voltage amplitude meter, a multiplier whose output is connected to the subtracting input of the algebraic adder, and the first input - to the output of the unit division, a voltage amplitude meter, the input of which is connected to the input of the voltage frequency meter, and the output is connected to the second input of the multiplier, a second comparator, the first input of which is connected the first input of the first comparator and with the output of the algebraic adder, the second input of the second comparator is connected to the output of the inverter, the input of which is connected to the second input of the first comparator and to the output of the first multiplier by a constant coefficient, and the output “Less” of the second comparator is connected to the input of the second actuator, the first shaper of rectangular pulses connected in series, the input of which is connected to the voltage input of the generator, and the shaper of the sequence of short pulses, the output of the cat The second is connected to the first input of the phase detector, the second square-wave pulse generator is connected in series, the input of which is connected to the input of the mains voltage, and the integrating amplifier, the output of which is connected to the second input of the phase detector, the third comparator, a low-pass filter, the input of which is connected to the output of the phase detector and the output is connected to the input of the third comparator, made in the form of a comparator with a zero threshold, the first element And, the first and second inputs of which are connected to the output "Less" of the first omparator and with the output “More” of the second comparator, respectively, a clock pulse generator, the output of which is connected to the first input of the second element And, the second input of which is connected to the output “More” of the third comparator, and the third input is connected to the output of the first element And, the first and second delay elements, the inputs of which are connected to the “Equal to” output of the third comparator, the first pulse counter is connected in series, the counting input of which is connected to the output of the second element And, and the input to the setting “0” - with the output of the first and the delay, the memory register, the control input of which is connected to the output of "Equal" of the third comparator, and the second multiplier by a constant coefficient, as well as the second pulse counter, the counting input of which is connected to the output of the second element And, the input input of the initial setting code is connected to the output of the second a multiplier by a constant coefficient, the control input of the second pulse counter is connected to the output of the second delay element, and the input to “0” is connected to the output “Equal” of the third comparator, and the overflow output of the second pulse counter xs is the output of the synchronization relay, and a constant-coefficient generating unit, the input of which is connected to the output of the memory register, and the output is connected to the constant-coefficient feed of the second multiplier by a constant coefficient, while the output “More” of the first comparator is connected to the input of the first actuator, meters the frequencies of the input and synchronized signals convert the input and synchronized signals in accordance with mathematical expressions U ₀ = A ₀ / f ₀ ; U ₁ = A ₁ / f ₁ , where U ₀ is the signal at the output of the voltage frequency meter; U ₁ is the signal at the output of the generator voltage frequency meter; f ₀ - network voltage frequency; f ₁ - generator voltage frequency; A ₀ , A ₁ - scale factors proportional to the amplitudes of the mains voltage and the voltage of the generator, respectively, and measuring the amplitude of the mains voltage and the voltage of the generator convert the mains voltage and the voltage of the generator into values proportional to their amplitudes and equal to A ₀ and A _1, respectively.

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