RU2215356C2 - Method for checking failure of automatic load transfer center in ring power mains - Google Patents

Abstract

FIELD: automatic control of power mains. SUBSTANCE: method used for checking failure of automatic load transfer center in ring power mains fed from different buses of double-transformer substation where automatic load transfer center is not provided with device inhibiting its closure to short circuit depends for its operation on recording inrush currents and counting time from moment of occurrence of first inrush short-circuit current at buses of main power supply transformer equal to time delay for closing automatic load transfer center; as soon as time counting is ceased, second inrush current exceeding rated value or short-circuit current at buses of stand-by power supply transformer is checked and if it fails, fact of automatic load transfer failure in ring power mains is stated. EFFECT: enlarged functional capabilities. 1 cl, 2 dwg

Description

 The invention relates to the automation of electrical networks and is intended to control the failure of the inclusion of the automatic transfer switch (ATS) point in a ring network powered by different buses of a two-transformer substation, and the ATS station is not equipped with a device for prohibiting its inclusion on a short circuit.

 A known method of controlling the failure of the automatic switch-on of the reserve for short circuit (short circuit) in the ring network, powered by two-transformer substation buses, which consists in fixing the surges of short-circuit currents and in measuring the time between them. Count the time from the moment of the appearance of the first inrush short-circuit current on the tires of the transformer of the main power source, equal to the time delay of the operation of the ABP network item, at the moment of the end of its countdown, the appearance of a second inrush current short circuit is controlled. on the tires of the backup power source and when it appears, the fact of the unsuccessful inclusion of the ABP point for a short circuit is established [1].

 The disadvantage of this method is the impossibility of using it to control the failure of the inclusion of an ABP point in a ring network.

 The objective of the invention is to expand the functionality of the method by obtaining information about the failure of the inclusion of an ABP point in a ring network powered by different buses of a two-transformer substation. In this case, the ATS item is not equipped with a device for prohibiting its inclusion in a short circuit.

 According to the proposed method, the appearance of an inrush caused by a short circuit in the line powered by this transformer is detected on the tires of the transformer of the main power source. When the appearance of an inrush short-circuit current, a countdown begins, equal to the delay time of the inclusion of the item ABP. At the end of this time, the appearance of a current surge is controlled (the current can increase to a value of a more normal operating current, not less than a short circuit current — an inrush current or up to a short circuit current — an inrush current) on the buses of a transformer for a backup power source. If at the end of the countdown there is no inrush on the tires of the transformer of the backup power source, then this indicates that there was a failure to turn on the ABP item.

The essence of the invention is illustrated using the drawings where:
figure 1 presents a structural diagram containing elements for implementing the method;
figure 2 - diagrams of the signals at the outputs of the elements shown in figure 1 with a short circuit at point 21 or 24 (see figure 1) in case of failure to enable the item ABP.

 The circuit (see Fig. 1) contains: ATS switch 1, current transformer 2, short-circuit current sensor 3, MEMORY element 4, DELAY element 5, single-vibrator 6, And 7 element, recording device (RU) 8, current transformer 9 , short-circuit current sensor 10, one-shot 11, element OR 12, element NOT 13 head switch of the main power supply line 14, section switch of the line 15, head switch of the line leaving the transformer bus of the backup power source 16, section switch of the line 17, main transformer isto nick supply 18, a backup power supply transformer 19, the substation section switch 20, the short-circuit point 21, users 22 and 23, the short-circuit point 24.

 The diagrams of the signals at the outputs of the elements shown in FIG. 1 during a short circuit at point 21 or point 24 (see FIG. 1) and the failure to turn on the ATS point have the form (see FIG. 2): 25 - at the output of element 2; 26 - at the output of element 3; 27 - at the output of element 4; 28 - at the output of element 5; 29 - at the output of element 6; 30 - at the output of element 9; 31 - at the output of element 10; 32 - at the output of element 11; 33 - at the output of element 12; 34 - at the output of element 13; 35 - at the output of element 7; 36 - the presence of information in element 8.

 In normal mode, the switch point ABP 1 is turned off and consumers 22 and 23 are fed through the head switch 14 and the sectional switch 15 from the buses of the transformer of the main power source 18. At the outputs of the current transformers 2 and 9 there is some value of the output signals (figure 2, diagrams 25, 30), due to operating currents, but insufficient for the operation of the short-circuit current sensors 3 and 10, and the single-shot element 11, so there are no signals at the inputs of the remaining circuit elements and the circuit does not start.

 In case of a short circuit at point 21 or point 24 (see Fig. 1), the output signal of current transformer 2 is sufficient to trigger the short-circuit current sensor 3 (Fig. 2, diagram 25), at the output of which a signal appears (Fig. 2, diagram 26) . This signal is stored by the element MEMORY 4 (figure 2, diagram 27) and is fed to the input of the element DELAY 5, from the output of which the signal will appear after a time equal to the delay time of the on-off switch of the ABP item (figure 2 diagram 28). The signal from element 5 will go to the input of one-shot 6, this element will give a single pulse (Fig. 2 diagram 29), which will "reset" the element MEMORY 4 and go to one of the inputs of the element And 7.

 If there is a failure of the ABP point for some reason, then its switch will not turn on, and therefore, the signal will not change at the output of current transformer 9 (Fig. 2, diagram 30), and there will be no inrush current and inrush current short circuits. Therefore, there are no signals at the outputs of the elements of the one-shot 11 and the short-circuit current sensor 10 (figure 2 diagram 32, 31). Accordingly, there is no signal at the inputs of the OR element 12 and at its output (Fig. 2 diagram 33). At the output of the element NOT 13 there is a signal (Fig. 2 diagram 34), which is fed to the second input of the element And 7. Therefore, a signal appears at its output (Fig. 2 diagram 35). This signal includes the RU 8 recording device. The RU 8 recording device contains information (Fig. 2, diagram 36) about the failure to turn on the ABP point in a ring network powered by different buses of a two-transformer substation.

 If the ABP item is turned on, then, at the output of the current transformer 9, there will be a signal sufficient to trigger the short-circuit current sensor 10, or the one-shot element 11 (for a short circuit at point 21 or 24, respectively). In this case, the one-shot element 11 will work if there is a surge in operating current that is more than normal. The signal from them will go to the input of the OR element 12, which means that the signal from the output of the element NOT 13 will disappear. There will be no signal at the second input of the And 7 element. Therefore, information will not be received in the RU 8 recording device.

 In case of failure to include the ABP point in the ring network, information about this on the basis of the proposed method will go to the maintenance personnel.

 Thus, the proposed method allows to provide timely information about the failure of the inclusion of the point ABP in the ring network, powered by different buses of a two-transformer substation. This will undoubtedly lead to an increase in the reliability of power supply to consumers through the adoption, on the basis of the information received, by the operational staff of the necessary decisions.

Sourse of information
1. RF patent 2169979 C1, 06/27/2001, cl. H 02 J 9/04 - prototype.

Claims (1)

 A method for monitoring the failure of turning on the automatic transfer switch (ATS) point in a ring network powered by different buses of a two-transformer substation, which consists in fixing two inrush currents and in counting the time from the moment the first inrush of a short circuit current occurs (short circuit) on the main transformer buses a power source equal to the time delay for turning on the ATS item, characterized in that at the time the time countdown ends, the appearance of a second surge of the operating current is greater than normal or short circuit current Nia busbar transformer backup power source, and if they are absent, then set the denial inclusion ABP points on the ring.

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