SU561251A1 - Device to protect the power plant from over-current signal level - Google Patents

Description

a half-wave faao-sensitive rectifier and a threshold block (or several), which consists of a sequentially connected discriminator of the amplitude, a separating element and 5

Hyper Met. The pilot signal source is connected in parallel with the device input and the sensor. At the input of the modulator, there is a sum of two signals: the sensor current and the source of the control signal source, which are opposite. When the sensor current is equal to O, only a source of the control signal is supplied to the modulator input, which is modulated, amplifying and transmitting to the phase-sensitive rectifier input 15. Under the influence of a rectangular voltage at the output of a phase-sensitive rectifier, the discriminator of the amplitude of the bu- acet will work in a dynamic mode, forming unipolar pulses. This voltage, 20 after the separating element, will be detected by alternating rectangular voltage, which is converted by the rectifier and constant voltage of a certain value and sign.

The presence of output voltage indicates that the specified level is not exceeded and that the device is operating normally.

With an increase in the sensor current, the total DZ signal acting at the modulator input decreases. This leads to a decrease in the signal at the input of the threshold block. When the sensor current reaches a certain predetermined value. 3 ,, at which the amplitude of the pulses entering the discriminator – amplitude input will become equal to its trigger threshold, the amplitude discriminator will no longer work in the shaping mode. Then the alternating voltage at the input of the output will disappear, which will lead to an abrupt disappearance of the output DC voltage, signaled when the input current exceeds a given level .45

In the case of any device, as well as in the power supply and control circuits of a sudden failure, leading to the disappearance of the control signal in the device path, the output voltage abruptly disappears, signaling a device malfunction. It is obvious that with such a construction of a protection device circuit, the occurrence of a 55

dangerous failure, i.e. there is no such situation in which the input signal reached a predetermined value, and the response did not occur. However prg. appearance at the output of a logic signal device80

it is impossible to establish the reason which caused it; it is impossible to distinguish the signal caused by the failure of any element from the c: fr-nal, which is due to the input signal having a predetermined value. For example, in the event of a malfunction, the amplifier signal appears on all threshold blocks, and if one of the elements of the threshold block abruptly fails, a logic signal appears on the output of this particular block.

The purpose of the invention is to increase the reliability and ease of operation of the device by indicating a fault signal.

The goal is achieved by the fact that a matching element and a low-pass filter are sequentially connected to the amplitude discriminator in each of the threshold blocks, the second input of each matching element connecting the first pulse width expander to the source of the control voltage, to the output of which The control unit, a signal source, is connected to the control unit, the output of the first pulse width expander is connected to the adder via the second pulse width expander, its other inputs, the number of oryh threshold equal to the number of blocks after the blocks included ng differentiating the low frequency output of the filter, and the output of the adder included formation unit. no fault signal. In order to eliminate the danger of failures, the coincidence unit is formed by two AND logic elements connected in parallel at the input, the output of which is connected to the inputs of a similar logic element I. In order to increase the reliability of the fault signal indication, the adder is formed by parallel switching at the input of logical elements AND, the number which and the number of inputs of each of them is one more than the number of threshold blocks, and their outputs are connected to the inputs of a similar logical element I.

FIG. 1 Hi and the functional diagram of the proposed device to protect the power plant against exceeding a predetermined level of the current signal; in fig. 2 is a schema of a match element; in fig. 3 - adder circuit; in fig. 4 - timing diagrams illustrating the operation of the device.

The device consists of a sensor 1, a source 2 of the control signal, a motor 3 with a source 4 of the control for the yarn, an amplifier 5, to the output of which are connected or opted for portative blocks, which are composed of successively connected discriminator Amshituoi O, coincidence element 10 and filter 11. Source 2 of the control cm of the connection is connected to the correct block 12 with the source 4 of the voltage across the output of which is connected through the first expander 13 of the duration of the pulses, inputs 14 all elements coincide tim 10 and the input of the second dilator 15, pulse duration. The inputs of the adder 16 are turned on through the differentiating units 17, the outputs of all the threshold units 6, 7, 8 and the BTO-iporo outputs of the pulse width expander 15, and the output of the adder 16 is connected to the malfunction signaling unit 18. The coincidence element 10 (Fig. 2) is formed by two parallel / Gg but switched on input logic gates And 18 and 1 The outputs of the And elements 18 and 19 are connected to the input of the similar element And 20 and its output is the output of the matching element. The adder (Fig. 3) is formed in parallel by the input elements And 21-24 logic elements, the number of which and the number of inputs of each of them are one more than the number of device threshold blocks. The outputs of these elements are included at the input of the logic element And 25, the output of which The output of the adder. The device works as follows. With a current of sensor 1 equal to O, only the current of source 2, the form of which is shown in FIG. 46. This signal is formed by a constant current Jxc I which is obtained after straightening and smoothing the alternating control voltage (Fig. 4, a) with short pulses of duration T2 on it, generated by means of the control unit 12. Rear edge of pulses The current of the control signal coincides with the front of the rectangular control voltage. After modulation and amplification, the voltage at the output of amplifier 5 is of the form shown in FIG. 4, c. This voltage is applied to the inputs of the threshold blocks 6, 7, 8, and under its influence the amplitude discriminators 9 operate in the shaping mode. The threshold for triggering the threshold unit 6 is indicated in FIG. 4, (Jj, a, the threshold of operation of the block 7 is Ts. The output of the discriminators 9 of the threshold blocks 6 and 7 is a pulsating voltage. As shown in Fig. 4g and 4 d, respectively. Obviously, the duration. amplitude discriminators are equal to T1 - the half-time of the control voltage. To the input J4 of the coincidence element 10 from the output of the first expander 13 impulses of TK duration are used (Fig. 4f. Since TZ T1, then the outputs of the coincidence 10 have single-pole pulses of T1 duration (. - Well, 4 h.). From this pool 1: sir its low-frequency filter voltages 11. output logic signals, isoperated in Figures 4 and 4, k., Since the signal corresponding to a logical unit is a constant voltage of a certain magnitude and sign imposed on it pulsations of the frequency using the differentiating unit 17 are pulses (Fig. 4 ln 4 m), the leading edge of which coincides with the trailing edge of the pulses at the output of the coincidence element 10, The pulses from the output of the differentiating blocks (the number of which is equal to the number of threshold blocks) served on input amounts torus 16. The voltage output from the first rasschiritel 13 is supplied to Vgoru rasshiritel15. Pulses with a duration of T4 from its output (Fig. 4n) are also fed to the input of adder 16. At the output of the adder, there are short pulses (Fig. 4o1 under the action of which a logical signal of malfunction is generated by block 18). 18 of the logical unit (Fig. 4 p). When increasing from the time i. The current of the sensor 1, the voltage at the output of the amplifier 5 begins to decrease, as the current of the sensor and the current of the control signal are directed oppositely. At the moment t, the voltage of the main modulating frequency is the input of the amggly-ore discriminator 9 by the r-horny block 6 becomes less than its threshold, triggered Uj (Fig. 4c), and the amplitude discriminator forms the output pulse, T2 duration, whereas before that it generated pulses, T1, The output of the coincidence unit 10 also receives a short pulse (Fig. 4g) at filter 11. This results in a decrease in the output logic signal. With a further increase in the sensor current, the output pulses of the coincidence unit are removed, short pulses of duration T2, and; At the output of the filter 11, a low constant is set. the voltage corresponding to a logical zero with a ripple imposed on it (Fig. 4, and) differentiating unit 17 selects pulses (fit 4a), the leading edge of which coincides with the falling edge of the pulses at the output of the matching unit, and therefore, the mode of operation the adder 16 and the malfunctioning signal generation unit do not change to the essence.

At the moment to, the voltage of the main modulating frequency decreases to a value less than ITjj and the pulse amplitude generated by the discriminator of amplitude 9 of the threshold unit 7 changes abruptly. At the output of the filter 11, the output voltage changes in a similar way (Fig. 4k) those. block 7 is operating. Obviously, in this the mode of operation of the adder 16 is not due to the enc etc, since short positive pulses are applied to its two inputs (Fig. 4 m and 4 n), and the third - by the duration T4 from the output of the second expander circuit 15 duration impulse.

With further increase of the sensor current at time t. - there is a change in the sign of the slowly varying signal acting at the input of the modulator 3, and therefore, the phase of the ex. The main frequency at the output of the amplifier 5, and at the moment: i: discriminator, amplitude 9 of the threshold unit 7 begins to generate pulses of duration T1 (a case is possible in which the duration of the pulse will be equal to T1 + T2). However, at the output of the coincidence block 1Q, there are ictuls with a duration TK - T1, approximately equal to T2. Therefore, the zero voltage output voltage varies slightly, and the positive pulse from the output of the diffinging unit is shifted to the right (somewhat zapaetsivae) relative to the front of the rectangular control voltage. This leads to a certain decrease in the pulse duration at the output of the adder 16, but does not disrupt the operation of the logical fault signaling unit 18.

At time t, the discriminator amplitude 9 of threshold block 6 begins to work in a similar way.

When the current of the sensor decreases to O, the changes described above occur in order.

Thus, a sign of proper operation of the device for protecting the power installation from exceeding a predetermined level of the current signal is the presence of a sequence (short pulses (Fig. 4 o)) at the output of the logic malfunction signal generating unit.

The output of this block contains a voltage corresponding to a logical one. When any sequence of triggering pulses disappears on any gfiigil or when the unit 18 itself malfunctions, no direct voltage is applied to the external circuit (logical, O). As shown above, the device is monitored regardless of the size and direction of the sensor and its changes over time.

The malfunction signal is given when a sudden failure occurs, which leads to the disappearance of the control signal in any functional element of the device.

Since one or several device threshold blocks are triggered by this, then, in order to prevent a device from malfunctioning, the logical fault signaling unit is made faster than the threshold blocks. When a sudden failure occurs, for example, in an amplifier.5, the sequence of triggering pulses arriving at the signal conditioning unit ... faults, and the pulses arriving at the low-frequency filter inputs of all threshold blocks, are simultaneously interrupted, but the output DC voltage disappears the output of the threshold blocks occurs at a lower speed than that of the disappearance of the voltage at the output of the malfunction signaling unit. Then the external circuit, processing the logical signals of the device, first receives a fault signal, and only then false logic signals from the outputs of the threshold blocks.

If the conventional circuit AND, for example, two series-connected transistor switches, were used as a match of the SRI 10, then when the transistor breaks down, the input of which receives a signal from the amplitude discriminator output, the threshold unit would not occur when the current increases sensor, t, .e. there would be a dangerous failure.

To prevent dangerous failure, the device due to the occurrence of an external failure in the coincidence element Yu, this element (see Fig. 2) is formed by two 18 and 19 parallel AND connected logical elements having two inputs each. . The outputs of elements 18 and 19 are connected to each other of a similar element AND 2O, ti its output is the output of a coincidence element 10,

According to a similar scheme, an adder 16 is built (Fig. 3). All input signals are inputs and inputs in parallel with included logical elements AND, 21-24, the number of which and the number of inputs each of them are one more than the number of threshold units of the device. The outputs of these elements are connected to the input of an element 25, the output of which is the output of an ohm adder,

At present, a device layout has been manufactured and eaten to protect it from exceeding a given signal level. The logic signal of the threshold units is given in the form of a DC voltage of 12 BS i20% (logical unit) and a DC voltage of less than 0.3 V (logic zero).

A malfunction signal is generated by simulating a sudden failure (interruption or short circuit) of any element included in the device.

The delay in the appearance of a false logical signal at the output of the threshold blocks in case of a sudden failure, according to the appearance of the malfunction signal, was in the test layout and can be easily increased.

Claims (1)

Invention Formula 1, A device for protecting a power plant against a predetermined level of a current signal, comprising a sensor and a source of a control signal, the output of which is connected in series with a modulator equipped with a source of control voltage,. and an amplifier, to the output of which threshold units are connected with amplitude discriminators at their inputs, is required so that, in order to increase reliability and ease of operation by indicating a device fault signal, in each of the threshold units An element in series is connected to the amplitude output of the amplitude discriminator and a low-frequency filter, the second input of each coincidence element being connected through the first pulse width expander to the control voltage source, to the output of which s the control unit is connected to the source of the control signal, the output of the first pulse width expander is connected to the sumator input through the second pulse extender, and the other the inputs, the number of which is equal to the number of the threshold blocks, are connected through the differentiating blocks to the outputs of low frequency frequencies, and the output unit of the signal generation unit is turned on, 2, The device according to claim 1, 1, so that, in order to eliminate the danger of failures, the coincidence element is formed by two AND logic elements connected in parallel at the input, whose outputs are connected to the inputs of the analogical AND logic element 3, The device according to claim 1, 1 and 2, so that, in order to increase the reliability of the indication of the device malfunction signal, the adder is formed by connecting the input logic elements AND, the number of which and the number of inputs, of each they are one more than the number of threshold blocks, and their outputs are connected with the inputs of a similar element AND, Sources of information taken into account in the examination: 1.2eciro e. Engineering- 39, N 474489 August 1967, No. 475, 553-557 September 1967, intended for the emergency protection system of a nuclear power plant in Wilf (England), 2, Copyright certificate No. 413567, on cl, H 02 H 9/02 for 1973, L R I fO 18 .I L. Fig.Z I