SU1390699A1 - Method of localizing a damaged section of power transmission line supplying serially connected dual-transformer substations with automatic section device for high and low voltages - Google Patents

Abstract

The invention relates to the emergency control automation of power lines for mainly agricultural purposes. The purpose of the invention is reliability. The goal is achieved by the fact that after the main switch (GW) is disconnected from the line, the sectional high-voltage devices (SKA HV) are disconnected at all two-transformer substations connected to the line. Automatic re-activation of the HV is applied to the nearest substation, where the normally disconnected sectional low-voltage apparatus (SKA HH) is turned on with a time delay. If this switch-on was successful, the SKA HH is turned off after the SCA HV is turned on and the same operations are performed on the subsequent substations until the power-on SKA HN is turned off from protection. Then similar operations are performed in the opposite direction, starting from a substation with a normally disconnected SKA HV. 1 il. S (L with so about b D G

Description

The invention relates to electric power industry, in particular, to methods of operation of emergency control systems of power lines 10-35-110 for mainly agricultural purposes.

The purpose of the invention is to increase reliability by simplifying the scheme implementing the method,

The drawing shows a diagram of a power line supplying series-connected two-transformer-mountain stations, and a block diagram of a control unit for a sectional switching apparatus of higher and Lower voltage at such a substation.

The power transmission line contains the main switches 1 and 2, the relay protection units 3 and two-time automatic reclosing device 4. The line includes two Transformer substations with Transformers 5 and 6, having a section switching device of high voltage (C HV) 7, a section of a low switching device (SCA HH) 8, switching devices (SC) 9 and 10 of the lowest voltage, and the SC 8.9 and 10 mO ty switch the current short circuit, the SKA 8 Low voltage is normally disconnected and, together with the SKA 7, the higher voltage is equipped control unit 11. The control unit includes a voltage control relay 12 and 13, a current sensor 14, a maximum Current relay 15, an AND 16-19 element cell, an OR 20 element, five delay elements 21-25, a HE element 26, and a memory element 27 28 (triggers).

In normal mode, the outputs of the relay 12 and 13, and therefore, the outputs of the elements 20 (OR) and 16 (AND) there is a signal corresponding to the logical unit. This signal from the output of the element And 16 is inverted by the element NOT 26, which leads to the appearance at the output of the element And 17 a logical zero, which goes to K - trigger input 27. At its second. at the input there is a logical unit, coming from the decode of the AND 16 element, which sets the trigger to the logical zero state at the output. At the output of the element And 18 - a logical zero, arriving at the S-input of the trigger 28, on the second input of which there is a .sh-logical unit.

with

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which leads to the appearance at the output of the trigger 28 a logical unit arriving at one input of the element 19. At the second input of this element comes a logical zero from the output of the element. AND 17, which sets the element AND 19 to the state of logical zero at the output.

In the event of a short-circuit on the line with a time delay of 1.5 s, the head switch 1 (2) is turned off by the action of protection 3, Block 4 of the JSA re-turns on the head switch. If it fails, then in a blank pause at the output of the AND element 16, a logical zero appears, which is inverted by the HE element 26 into a logical unit. This signal, with a delay of 4 s, generated by the delay element 21, is applied to the high-voltage cut-off coils of the higher voltage and is disconnected.

Then follows the switching of the main switch from the automatic reclosing of the second cycle. Since the voltage was generated from one side of the highest voltage closest to the main circuit breaker SKA, a logical unit appears at the output of the OR element 20 of its control unit. At the output of AND 17, a signal of a logical unit also appears, which sets the trigger 27 to the state of a logical one at the output. This signal arrives at one input of the element And 18, but since its other input is a logical zero signal, there is also a logical zero signal at the output, which goes to the S input of the trigger 28, its other input contains a logical zero, the arrival the output of the element And 16, which leads to the preservation at the output of the trigger 28 logical unit arriving at the input element And 19, At its other input with a delay created by element 23 and is 2c, the signal of the logical unit, which leads to the appearance of the element output 19 logical unit, and therefore to the inclusion of the SKA lower voltage. If the latter is turned on to the undamaged area, then after a time of 1 s, created by the delay element 25, the high voltage SKA turns on, followed by the low voltage SKA disconnecting,

If the lower voltage SCA is turned on to the damaged section, then the output of the relay 15 is a signal of the logical unit, which after a time of 0.5 s created by the delay element 22 enters the input of the element 18. As its second input If the signal of a logical unit is present, then And 18 is the logical unit at the output of the element, which translates trigger 28 into the logical zero state at the output. After switching off the low voltage SCA, logical zeros arrive at both inputs of the trigger 28, which preserves the logical zero at its output.

Thus, the signal to turn on the SKA of the lower and higher voltage is not received.

After time 5c, created by the delay element 24, the switching-off apparatus 9 or 10 of the lower voltage of the de-energized transformer disconnects and the lower-voltage SKA turns on, which restores the power supply to the consumers of the disconnecting transformer,

At the substation, where the SKA VN is normally disconnected, the activation of the SKA NP is delayed

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hp

where n MaKcCk ,, L is the number of substations to the right and left of the specified substation

 the time from the moment of occurrence of a fault on the line to the moment of switching on the TV from the automatic reclosing of the second cycle j Dt is the time delay stage,

and the operations are repeated as described before the release of the damaged area from the side of the backup power supply.

At the substation with normally disconnected SKA HV, the time delay for switching off switching devices 9 and 10 from the ATS circuit is increased by t t

Thus, the invention makes it possible to use high-voltage as section switching devices.

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Substation voltage is simplified switching devices - load switches. This leads to simplification and reduction in the cost of control units for these devices, as well as lower labor costs for commissioning and maintenance of these units.

Claims (1)

Invention Formula A method for isolating a damaged section of a power line supplying series-connected two-transformer substations with automatic sectional apparatus at higher and lower voltages, in which the first is disconnected at one of the substations, the second (capable of switching the fault current) is disconnected at all substations, and the main switch the lines are equipped with relay protection and double automatic reclosing; when a permanent damage occurs on the line, the sectional devices of the highest voltage closest to the place of damage are disconnected at the beginning from the main, and then from the backup power, characterized in that, in order to increase reliability by simplifying the scheme that implements the method, when a permanent damage occurs on the line, its main circuit breaker is disconnected after unsuccessful automatic reclosing for the time longer than specified, sectional devices of higher voltage are disconnected at all substations, the second automatic reclosing device switches on the head switch of the line and when voltage appears at the substation closest to it with you The time section includes a low-voltage sectional apparatus installed on it, if a short circuit current is then wired, then this device is disconnected and, if there is an AVR at the lower voltage, start the circuit of this AVR, and otherwise (the short circuit current is not J) the indicated apparatus is turned off after switching on the sectional apparatus of higher voltage and the similar operation of the automatics on the subsequent substations along the power path, a damaged section is isolated, while at the substation with a normally disconnected sectional Parameters of higher voltage sectional apparatus lower on 513906996 The yarns are connected with a delay greater than that of such apparatuses at the substations connected to the line than the total turn on time of all. 3 I I  I GUY tueuiet I 9tntte49itu9 fg hututfi fftrirfMMItlltUf CKA tueuiet Hunff enuX t1