RU2231852C1 - Frequency-phase relay - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: proposed frequency-phase relay can be utilized in the capacity of frequency-phase difference relay controlling frequency and phase of voltage of generator with reference to frequency and phase of network voltage. Frequency-phase relay has three actuators, four comparators, three AND gates, two formers of short pulses of leading edge, two frequency meters, two amplitude meters, multiplier, divider, multiplier of constant coefficient, algebraic adder, two inverters. Meters of frequency of network and generator convert signals of network and generator in correspondence with mathematical expressions U₀=A₀/f₀, U₁=A₁/f₁, where U₀ is signal across output of network frequency meter; U₁ is signal across output of generator frequency meter; f₀ is network frequency; f₁ is generator frequency; A₀,A₁ are scale coefficients proportional to amplitudes of voltages of network and generator. Meters of amplitudes of network and generator convert signals of network and generator to values proportional to their amplitudes and equal to coefficients A₀ and A₁ correspondingly. Duration of pulses formed by first and second formers of short pulses of leading edge is proportional to permissible value of mismatch of phases of voltages of network and generator and duration of pulses formed by pulse stretcher is less than period of voltage of generator and period of voltage of network.

EFFECT: expanded functional potential of frequency-phase relay by control over frequency and phase of voltage of generator with reference to frequency and phase of voltage of network.

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Description

The invention relates to electrical engineering and can be used as a frequency-phase differential relay that controls the frequency and phase of the generator voltage relative to the frequency and phase of the mains voltage.

A device is known that contains a series-connected clock generator, a binary pulse 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 frequency-phase relay.

Closest to the technical nature of the claimed is a device containing a series-connected isolation transformer, a frequency filter, a first frequency-dependent element, a first threshold block, an element BAN, a pulse expander, an amplifier and an executive element, a second frequency-dependent element, the input of which is connected to the output of the frequency filter, and the output through the key is connected to the second input of the first threshold block, a voltage divider connected in series, the input of which is connected to the output a frequency filter, a second threshold unit and differentiating element, the output of which is connected to the second input of the differentiating element and the trigger element having an input connected to the output isolation transformer and an output - is connected to the second input of the pulse expander [2].

The disadvantage of the closest technical solution is the relatively narrow functionality, since it can simultaneously operate either as a frequency lowering relay or as a frequency increasing relay and does not allow controlling the frequency and phase of an external generator in relation to the frequency and phase of the network.

The required technical result is to expand the functionality by providing control of the frequency and phase of the generator voltage relative to the frequency and phase of the mains voltage.

This technical result is achieved by the fact that a generator amplitude meter, a network amplitude meter, an algebraic adder, a constant coefficient multiplier, a multiplier, a first and a second inverters, a third and a fourth are introduced into the device containing the first and second comparators, the division unit and the first actuator. comparators, second and third actuators, first, second and third AND elements, first and second pulse shapers on a rising edge, a network frequency meter, the input of which is connected to the course of the network amplitude meter is the input of the frequency-phase relay network, and the output is connected to the input of the multiplier by a constant coefficient and to the addition input of the algebraic adder, the generator frequency meter, the input of which is connected to the input of the generator amplitude meter, and the output is connected to the input of the divisible division unit the input of the divider of which is connected to the output of the generator amplitude meter, and the output is connected to the first input of the multiplier, the second input of which is connected to the output of the network amplitude meter, and the output is connected n with a subtracting input of the algebraic adder, the output of which is connected to the first inputs of the first and second comparators, the second input of the first comparator is connected to the output of the multiplier by a constant coefficient and to the input of the first inverter, the output “more” of the first comparator is connected to the input of the first actuator, the second input the second comparator is connected to the output of the first inverter, and the output “less” is connected to the input of the second actuator, while the input of the first pulse shaper on the leading edge is dined with the output of the third comparator, the input of which is connected to the input of the generator amplitude meter, which is the input of the frequency-phase relay generator, the input of the second pulse shaper is connected to the output of the fourth comparator with the output of the fourth comparator, the input of which is connected to the input of the network amplitude meter, the first and second inputs of the second element And are connected to the outputs of the first and second pulse shapers, respectively, on the leading edge, and the output is connected to the input of the pulse expander, the output of which is connected to the input the second inverter, the output of which is connected to the first input of the third element And, the second input of which is connected to the output of the first element And, the first and second inputs of which are connected to the output “less” of the first comparator and with the output “more” of the second comparator, respectively, the output of the third element And connected to the input of the third actuator, the frequency meters of the network and the generator convert the network and generator signals in accordance with the 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 frequency meter,

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

f ₀ - network frequency,

f ₁ - generator frequency,

A ₀ , A ₁ - scale factors proportional to the amplitudes of the voltage of the network and the generator, and the meters of the network and generator amplitudes of the network and generator signals are proportional to their amplitudes and equal to the scale factors A ₀ and A _1, respectively, the duration of the pulses generated by the first and the second pulse shapers on the leading edge, is proportional to the permissible value of the phase voltage mismatch between the generator and the voltage, and the duration of the pulses generated by the pulse expander is not less than and the generator voltage and the mains voltage period.

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

The frequency-phase relay (Fig. 1) contains the first 1 and second 2 comparators, a division unit 3, a first actuator 4, a generator amplitude meter 5, a network amplitude meter 6, an algebraic adder 7, a constant coefficient multiplier 8, the first 9 and second 10 inverters, the third 11 and fourth 12 comparators, the second 13 and third 14 actuators, the first 15, the second 16 and the third 17 elements And, the first 18 and the second 19 are pulse shapers on the leading edge, a network frequency meter 20, the input of which is connected to the input meter 6 amplitude set and is the voltage input of the frequency-phase relay network, and the output is connected to the input of the multiplier 8 by a constant coefficient and to the addition input of the algebraic adder 7, the generator frequency meter 21, the input of which is connected to the input of the generator amplitude meter 5, and the output is connected to the input of the divisible block 3 division, the input of the divider is connected to the output of the amplitude meter 5 of the generator, and the output is connected to the first input of the multiplier 22, the second input of which is connected to the output of the meter 6 of the network amplitude, and the output is connected to the subtraction the input input of the algebraic adder 7, the output of which is connected to the first inputs of the first 1 and second 2 comparators, the second input of the first comparator 1 is connected to the output of the multiplier 8 by a constant coefficient and to the input of the first inverter 9, and the output “more” is connected to the input of the first actuator 4. The second input of the second comparator 2 is connected to the output of the first inverter 9, and the output “less” is connected to the input of the second actuator 13. The input of the first pulse former 18 is connected to the output of the third a comparator 11, the input of which is connected to the input of the generator amplitude meter 5, the input of the second pulse former 19 is connected to the output of the fourth comparator 12, whose input is connected to the input of the network amplitude meter 6, the first and second inputs of the second element And 16 are connected to the outputs, respectively the first 18 and second 19 pulse shapers on the leading edge, and the output is connected to the input of the expander 25 pulses, the output of which is connected to the input of the second inverter 10, the output of which is connected to the first input third the first element And 17, the second input of which is connected to the output of the first element And 15, the first and second inputs of which are connected to the output “less” of the first comparator 1 and with the output “more” of the second comparator 10, respectively, and the output of the first element And 15 is connected to the second the input of the third element And 17, the output of which is connected to the input of the third actuator 14.

Actuators 4, 13 and 14 can be made in the form of relay windings with make or break contacts. Shapers 18 and 19 generate a short pulse when their input signal drops from a lower level to an upper one.

The frequency meters of the network 20 and the generator 21 convert the signals of the network and the generator in accordance with the 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 frequency meter,

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

f ₀ - network frequency,

f ₁ - generator frequency,

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

The amplitude meters of the network 6 and the generator 5 convert the signals of the network and the generator into values proportional to their amplitudes and equal to the scale factors A ₀ and A _1, respectively.

The duration of the pulses generated by the first 18 and second 19 pulse shapers on the leading edge is proportional to the permissible value of the phase voltage mismatch between the generator and the generator, and the pulse duration generated by the expander 25 pulses is not less than the generator voltage period and the network voltage period.

The remaining units of the device are standard units of electrical engineering. The power circuits of the blocks in the drawing are omitted as non-essential.

The frequency meters 20 and 21 (FIG. 2) can be made in the form of an amplifier 23, in the output circuit of which a resonant circuit 24 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 the signals at the output of the fourth comparator 12 (Fig.3, a) and at the output of the third comparator 11 (Fig.3, b, c, d). The shaded parts correspond to the duration and temporary position of the pulses generated by the formers, included at the outputs of the respective comparators.

Frequency-phase relay operates as follows.

When the relay is turned on, the signal U ₀ = A ₀ / f ₀ is formed at the output of the meter 20, the value of which is inversely proportional to the frequency of the mains voltage 1 / f ₀ , and at the output of the meter 21, the signal U ₁ = A ₁ / f ₁ is inversely proportional to the generator frequency f ₁ . At the same time, meter 6 generates a signal proportional to A ₀ , and meter 5 produces a signal proportional to the amplitude of A ₁ . In this case, at the output of the algebraic adder 7, 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 ₀ = f ₁ .

In addition, the signal from the output of the meter 1 is multiplied in the multiplier 2 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 1, 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 2, the quantities A ₀ (f ₁ -f ₀ ) / f are compared $\genfrac{}{}{0ex}{}{\text{2}}{\text{0}}$ and - A ₀ K / f ₀ , since the signal from the output of the multiplier 8 inverted by the first inverter 9 is input to it.

The first actuator 4 will work when the frequency of the generator f ₁ exceeds the permissible deviation from the network frequency f _o upward by a relative amount specified by the coefficient K, and the second actuator 13 when the frequency of the input signal is unacceptably deviated downward. If the generator frequency coincides with the frequency of the network or deviates from it within acceptable limits, then a logical unit signal will be generated at the output of the first element And 15, allowing the adjustment of the generator voltage phase to the network voltage phase. This will happen if there is an unacceptable phase mismatch using the third actuator 14, if it receives a logical unit signal from the output of the third element And 17. The formation of such a signal or a logic zero signal is as follows.

The voltage of the network is supplied to the input of the fourth comparator 12 (with a zero threshold level), and the generator voltage is supplied to the input of the third comparator 11 (also with a zero threshold level), so a sequence of rectangular pulses is formed at the output of the fourth comparator 12 (Fig. 3, a), the duration of which is equal to half the period of the voltage of the network, and at the output of the third comparator 11 a sequence of rectangular pulses is formed (Fig. 3, b, c, d), the duration of which is equal to half the period of the voltage of the generator. The first 18 and second 19 shapers produce short pulses, the duration of which is proportional to the permissible value of the phase mismatch of the input signals (shaded parts of the signals in figure 3).

With the coincidence of the temporary positions of the pulses, for example in Fig. 3, a and Fig. 3, b, a pulse is generated at the output of the second element And 16, which is expanded by the expander 25, but converted into a logical zero level by the second inverter 10. Therefore, even if there is a logical level units at the output of the first element And 15 the third actuator 14 does not work.

When the phase voltage of the generator relative to the phase of the mains voltage exceeds the allowable limit specified by the duration of the pulses generated at the outputs of the first 18 and second 19 pulse shapers on the leading edge, the pulses from the output of the second shaper 19 cease to coincide in time with the pulses generated at the output of the first shaper 18 therefore, at the output of the second element And 16 no corresponding coincidence pulse is formed and at the output of expander 25 there will be a level of logical zero, which is inverted is taken by the second inverter 10. Therefore, if there is a level of a logical unit at the output of the first element And 15, which signals a sufficient proximity of the frequencies of the voltage of the network and the generator, a level of a logical unit is formed at the output of the third element And 17, which, in turn, triggers the third actuator 14.

Thus, the proposed device has wider functional capabilities, since it not only generates a signal characterizing the presence of network and generator signals, but also generates an unacceptable signal of phase voltage mismatch between the generator and the network when determining the proximity of their frequencies.

Sources of information

1. Electrical reference book, in 4 volumes, t.2. Electrical products and devices. Under the general editorship of V.G. Gerasimova et al. - Moscow: 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.122, Fig.3.29 (prototype).

Claims (1)

Frequency-phase relay, containing the first and second comparators, the division unit and the first actuator, characterized in that the generator has an amplitude meter, a network amplitude meter, an algebraic adder, a constant factor multiplier, a multiplier, the first and second inverters, the third and fourth comparators , the second and third actuators, the first, second and third elements And, the first and second drivers of short pulses on the leading edge, the frequency meter of the network, the input of which is connected to the input and the network amplitude meter is the network input of the frequency-phase relay, and the output is connected to the input of the multiplier by a constant coefficient and to the addition input of the algebraic adder, the generator frequency meter, the input of which is connected to the input of the generator amplitude meter, and the output is connected to the input of the divisible division unit, the input of the divider which is connected to the output of the generator amplitude meter, and the output is connected to the first input of the multiplier, the second input of which is connected to the output of the network amplitude meter, and the output is connected to the subtractor by the input of an algebraic adder, the output of which is connected to the first inputs of the first and second comparators, the second input of the first comparator is connected to the output of the multiplier by a constant coefficient and to the input of the first inverter, the output “More” of the first comparator is connected to the input of the first actuator, the second input of the second comparator connected to the output of the first inverter, and the output “Less” is connected to the input of the second actuator, while the input of the first driver of a short pulse on the leading edge with connected to the output of the third comparator, the input of which is connected to the input of the generator amplitude meter, which is the input of the frequency-phase relay generator, the input of the second short-pulse driver for the leading edge is connected to the output of the fourth comparator, the input of which is connected to the input of the network amplitude meter, the first and second inputs the second element And are connected to the outputs of the first and second short pulse shapers, respectively, on the leading edge, and the output is connected to the input of the pulse expander, the output of which connected to the input of the second inverter, the output of which is connected to the first input of the third element And, the second input of which is connected to the output of the first element And, the first and second inputs of which are connected to the output “Less” of the first comparator and the output “More” of the second comparator, respectively, the output of the third element And is connected to the input of the third actuator, the frequency meters of the network and generator convert the signals of the network and generator 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 frequency meter; U ₁ - signal at the output of the generator frequency meter; f ₀ - network frequency; f ₁ - generator frequency; And ₀ , And ₁ - scale factors proportional to the amplitudes of the voltage of the network and generator, moreover, the meters of the network and generator amplitudes convert the signals of the network and the generator into values proportional to their amplitudes and equal to the scale factors A ₀ and A _1, respectively, the duration of the pulses generated by the first and second shapers of short pulses along the leading edge is proportional to the allowable value of the phase voltage mismatch of the network and generator, and the duration of the pulses generated by the pulse expander is not less than the generator voltage period and the network voltage period.

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