RU20759U1 - AUTOMATIC DRAINAGE INSTALLATION - Google Patents

Description

AUTOMATIC DRAINAGE INSTALLATION

Kandaev Vasily Andreevich Sveshnikova Natalya Yuryevna Kandaev Andrei Vasilyevich

MKIS23R 13/00

The utility model relates to the field of corrosion protection against stray currents of oil and gas pipelines laid along a direct-current electrified railway, as well as metal sheaths of power supply cables, communications, signaling cables, centralization, blocking in railway transport.

A reinforced drainage installation is known, which is a direct current source connected between the protected structure and the midpoint of the inductor-transformer. In addition to the function of current drain in one direction, provided through the rectifier device, the protection effect is enhanced by the action of a constant current source. At low values of the drainage current, when the minimum protective potential of the structure is not provided, an additional source is included in the drainage circuit, which ensures the maintenance of the potential of the structure - the earth within specified limits. (A.S. 842680 USSR, MKI C23F 13/00. Reinforced electric drainage device for protecting underground metal structures from corrosion caused by stray currents / Levin V.M., Tarnizhevsky M.V., Lomanovich V.A. et al. / / Discoveries. Inventions. 1963.- No. 10).

The disadvantage of this installation is that with a significant potential difference between the structure and the rail, a potential is formed on the protected structure, the value of which is less than the minimum allowable.

The closest in technical essence to the proposed utility model is an automatic drainage installation containing a drainage circuit of a series-connected fuse, knife switch, pgunt with a measuring device and a power switch, a reference electrode, a control unit consisting of a reference voltage source, a clock pulse generator, sawtooth shaper voltage, error signal amplifier, comparator, comparator, counting trigger, first and second matching circuits, IL circuit . (A. p. 16739 Russian Federation, MKI C23F 13/00, Automatic drainage installation / Kandaev V.A., Sveshnikova N.Yu.).

The disadvantage of this drainage installation is that there may be potentials of large values established by GOST on the protected structure. (GOST 9.602-89 Underground structures. General requirements for protection against corrosion. M: GKS, 1989, 54p.).

The purpose of the utility model is to optimize the protection of underground structures by maintaining the protective potential of the structure within the limits established by GOST. (GOST 9.602-89 Underground structures. General requirements for protection against corrosion. M: GKS, 1989, 54p.).

This goal is achieved by the fact that in an automatic drainage installation containing a drainage circuit from a series-connected guard, a knife switch, a shunt with a measuring device and a power switch, a reference electrode, a control unit consisting of a first reference voltage source, a clock pulse generator, sawtooth shaper , an error signal amplifier, a comparator, a first comparator, a counting trigger, a first and second matching circuit, C3tb or OR, a rectifier is introduced ost, direct current source, measurement circuit, consisting of the second and third comparators and the second voltage reference source, and the diagonal of the rectifier bridge 24 - 25 is connected between the rail and the protected structure through the drainage circuit, the protected structure is connected to the non-inverting input of the second comparator, to the inverting input the third comparator and to the first input of the comparator, the first output of the second reference voltage source is connected to the inverting input of the second comparator, the second output is W The other voltage reference source is connected to the non-inverting input of the third comparator, the output of the reference electrode is connected to the common wire of the measurement circuit and the control unit of the automatic drainage system, the output of the second comparator is connected to the control input of the DC source, the outputs of the DC source are included in the diagonal 26-27 of the rectifier bridge , the output of the third comparator is connected to the third inputs of the first and second matching circuits of the power switch control unit.

In FIG. 1 shows a functional diagram of the proposed automatic drainage installation, in FIG. 2 - 9 - waveforms at the outputs of the elements of the functional diagram.

The automatic drainage installation (Fig. 1) contains a fuse 1, a switch 2, a shunt 3 with a measuring device 4, a power switch 5, a reference electrode 6, a control unit 7, consisting of and a comparator 8, the first reference voltage source 9, a clock generator 10, a sawtooth voltage shaper 11, an error signal amplifier 12, a first comparator 13, a counting trigger 14, matching circuits 15, and

16, OR circuit 17, rectifier bridge 18, direct current source 19, measurement circuit 20, consisting of comparators 21 and 22 and a second reference voltage source 23.

Installation works as follows.

Depending on the distribution of currents in the rail-ground-underground system, the following situations are possible:

I: The potential underground structure - the earth is larger than the upper boundary of the protective potential of the structure ();

2. Potential underground structure - land located within the boundaries of the protective potential of the structure ();

3. The potential underground structure - land is smaller than the lower boundary of the protective potential of the structure ().

In this regard, there are three modes of operation of the automatic drainage installation.

The potential of the underground structure - the ground, defined relative to the reference electrode 6, is fed to the non-inverting input of the comparator 21 and to the inverting input of the comparator 22, where it is compared with the reference voltages of the second source 23. In the comparator 21, a comparison is made with the upper boundary of the protective potential, which is fed to the inverting input comparator 21 from the first output of the second reference voltage source 23. If the potential value of the underground structure is the earth above the upper boundary, then the control signal from the input of the computer the radiator 21 is fed to the control input of the direct current source 19, which creates a current in the drainage circuit that provides the necessary protective potential of the underground structure.

The comparator 22 compares the potential of the underground structure - the earth (fed to the inverting input of the comparator 22) with the lower boundary of the protective potential (fed to the non-inverting input of the comparator 22 from the second output of the second reference voltage source 23). If the value of the potential of the underground structure - the earth is less than the lower boundary, then the control signal from the high-voltage signal of the comparator 22 is fed to the third inputs of the matching circuit 15 and 16, allowing the operation of the control side of the power switch. Underground potential - ground, determined with respect to reference electrode 6, is supplied to the input of the comparison device 8, where it is compared with the reference voltage of the first source 9. From the output of the comparison device 8, the error signal is supplied to the amplifier of the error signal 12, from the output of which the analog voltage UO is applied to the first input of the comparator 13. The sawtooth voltage Un (Fig. 3) is supplied to the second input of the first comparator, which is generated in the sawtooth voltage shaper 11 and synchronized by a clock generator pulses 10 (figure 2). Signal

Error U01 corresponds to a pulse of duration tl, and a signal of 1102 corresponds to a pulse of duration t2. The pulses of the clock generator (Fig. 2) are supplied to the counting trigger 14. At the non-inverting output of the trigger 14, rectangular pulses Utl having a duration T and a repetition period of 2T are obtained (Fig. 4). At the inverting output of the counting trigger 14, the positive rectangular pulses Ut2 are shifted in comparison with Utl by half the period, i.e. on T (Fig. 5). At the output of the comparator 13, pulses with a PWM are obtained, the duration of which is the shorter, the larger the error signal (Fig. 6). The pulse sequence Utl is fed to the input of the matching circuit 15, and the sequence Ut2 is fed to the input of the matching circuit 16. At the output of the matching circuits, we obtain P1 pulses UB1, UB2 corresponding in duration to the overlapped part of the pulses of the sequences UH and Utl (UB1) and Ш and Ut2 (UB2) (Fig. 7.8). Having added up the voltages from the outputs of matching circuits 14 and 15, at the output of the circuit ШШ 17, we obtain a pulse sequence with a period T and duty cycle varying from 1 to oo (Fig. 9).

At the output of the control unit, pulses are formed, the duration of which is the shorter, the greater the potential of the building - the ground. The sequence of pulses controls the operation of the power switch 5. Thus, during the duration of the pulse, the switch is in the on state, and there is a withdrawal of the inrush currents from the underground structure to the rails. During a pause, the switch is turned off, the circuit breaks.

If the potential value of the underground structure - the earth is greater than the lower boundary of the protective potential and less than the upper one, at the outputs of the second and third comparators - logic zero, the DC source is turned off, the power switch is closed, the automatic drainage system operates in polarized drainage mode.

The drainage device is protected against overloads by means of a fuse I installed in the drainage circuit.

The value of the drained current is determined using a measuring device 4 with a shunt 3.

Thus, the introduction of a rectifier bridge, a direct current source, a measurement circuit consisting of the second and third comparators and the second reference voltage source p into the automatic drainage installation allows maintaining the protective potential of the structure in predetermined limits for all possible values of the current distribution in the rail-ground system, f underground construction, than to ensure trouble-free operation of the underground structure for the entire period of operation.

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Claims (1)

An automatic drainage installation comprising a drainage circuit of a fuse, a circuit breaker, a shunt with a measuring device and a power switch, a reference electrode, a control unit consisting of a first reference voltage source, a clock pulse generator, a sawtooth voltage generator, an error signal amplifier, a comparison device, first comparator, counting trigger, first and second matching circuits, OR circuits, characterized in that a rectifier bridge, a source are introduced into it direct current measurement circuit consisting of the second and third comparators and the second voltage reference source, the diagonal of the rectifier bridge 24-25 being connected between the rail and the protected structure through the drainage circuit, the protected structure is connected to the non-inverting input of the second comparator, to the inverting input of the third comparator and to the first input of the comparator, the first output of the second voltage reference source is connected to the inverting input of the second comparator, the second output of the second source the reference voltage is connected to the non-inverting input of the third comparator, the output of the comparison electrode is connected to the common wire of the measurement circuit and the control unit of the automatic drainage unit, the output of the second comparator is connected to the control input of the DC source, the outputs of the DC source are included in the diagonal 26-27 of the rectifier bridge, the output the third comparator is connected to the third inputs of the first and second matching circuits of the power switch control unit.