SU845211A1 - Device for monitoring synchronism at automatic reconnection of power transmission line - Google Patents

Description

ment “Delay on return. In this case, the second input of the second element I is intended for connection to the first output of the AR unit.

Considering that the response characteristic of the device 3 has a straight view on the 6-S plane, its operation can occur only if the measurement starts at angles not exceeding the angle of response, otherwise it will only be possible in the next cycle, after cranking the vectors of the stresses being compared. It should also be noted that the response time of such an ACS depends on the amount of slip, it increases with decreasing slip.

Thus, the known device with a small slip has either a very long time of action, or does not work at all. As a result, it cannot be used to effect automatic reclosing with synchronization control. It can only be used to capture synchronism.

The aim of the invention is to increase the speed and reliability of the ACS by ensuring that it operates at low slip.

This is achieved by the fact that in a known synchronism control unit with an automatic restart (AR) of a power line equipped with a voltage transformer and an AR unit and connected to the plugs of a substation equipped with a voltage transformer containing a phase shift unit whose two inputs are intended for. connecting the transformer. I voltage the line and bus, respectively, the first output of the phase shift block is connected to the input of the slip block, and the second output is connected to the first input of the first sum of the matrix, the second input of which is connected to the slip block output, the output of the first adder through the first threshold unit is connected to the first input of the element I, the second input and the output of which are intended to be connected respectively to the first output and the permitting input of the automatic reclosing unit; the first, second detectors, the second adder and the threshold unit are additionally introduced, Rich second output of the phase shift unit is connected to a first input of the second adder unit output sliding through the first and second detectors coupled to second inputs of the first and second adders, the output of the second adder via a second threshold unit

connected to the third input of element I.

FIG. 1 shows the structural scheme of the proposed synchronization control authority in the case of automatic transmission of the power line; in fig. 2 is a characteristic of its operation in the 5-S plane.

In the diagrams: 1 - power lines; 2 - line switch; 3 - tires; 4, 5 — measuring transformers of line voltage and busbars, respectively; 6 - AR unit; 7 - synchronism control authority, which includes: 8 - phase shift block; 9 - clutch unit; 10, 11 — detectors included in the forward and reverse directions, respectively; 12, 13 - the first and second adders; 14 - the first threshold unit; 15 - the second threshold unit; 1b - element I.

The voltage of line 1 and busbar 3, which are compared with each other in phase, through measuring transformers 4 and 5 are supplied to both inputs of phase shift unit 8. In block 8, a voltage is formed that is proportional to the magnitude of the angle b and coincides with it in sign.

U5 KiS, (1)

where Ki is the proportionality coefficient.

The voltage U from the first output of block 8 is fed to the input of block 9 slip. In block 9, a voltage Ug is formed, proportional to the magnitude and sign of the slip

Us Cg-s (2)

where Cg is the coefficient of proportionality.

From the second output of block 8, the voltage Us is supplied to the first inputs of the first 12 and second 13 adders, the second inputs of which are supplied respectively with positive and negative voltages and $ from the output of block 9 through the detectors 10 and 11. Output voltages of adders 12 and 13 arrive respectively at the inputs of the first 14 and second 15 threshold blocks. In block 14, an inverse output is used. The signal at this output exists as long as the input voltage of the block does not exceed the threshold level and,..., Which is a positive value. In block 15, a direct output is used, the signal at which appears when the input voltage of the block exceeds a threshold level and is the corresponding value. The inverse output of the block 14 and the direct output of the block 15 are connected to the first and second inputs of the element 16, the third input and the output of which are intended to be connected respectively to the first (starting) output and the enable input of the AR block b. Unit 6 has the first and enable inputs, rtepvy (start) and the second (including) outputs. The signal at the first output appears immediately after the appearance of the signal at the first input. The signal at the second output appears only when there is a signal at the first and enable inputs. The signal at the output of element 16I, which is the output of the ACS 7 as a whole, appears when there are signals on all three inputs of this element, namely, if there are signals from both threshold blocks 14, 15 and a signal from the first (starting) output of the AR .

Claims (3)

To clarify the operation of the ACS and the type of its response characteristic, it is advisable to consider in turn the operation of two adders and the associated threshold units. The first adder 12 is supplied with the voltage and the positive values of the voltage Us. The signal conditions at the inverse output of the first threshold unit 14 correspond to the expression KiS + KZ.S U „op. at S 0, (Ki8 Unop. at S 0, here Unop./ 0 is the response voltage of the first threshold unit 14. From expressions (3) it can be seen that, when Ug KzS 0 (s 0), the operation of block 14 will occur with positive In the plane (Fig. 2) this will correspond to point B. The angle SB for this point is determined by the expression (3) and is (4) The signal on the inverse output of block 14 will exist for all values of angle 8, lying to the left of point B, and for s with O, to the left of direct sun. At s 0, the operation of block 14 will occur at smaller angles 5, since and 0, and acts in the same direction as U5. Therefore, the range of operation of the block will be limited to direct AB, the slope of which is determined by the coefficient Kr. Thus, for positive s and S 0, the slip of Si is determined from expressions (3) and ( 4) ITnop, K..sch Kg Thus, the signal at the inverse output of block 14 will exist at ratios between 5 and S, defined by the region lying to the left and below the broken line ABC. The second adder is supplied with a voltage and § and negative voltage values Ug. The conditions for the occurrence of the signal at the output of the second threshold unit 15 correspond to the expression KiS + KaS and the order of 1 s 1, () .i at s X, where and „di 0 - | 1 creep action of the second threshold unit 15. From the expressions (8 ) it is seen that at U5 О (s 0) the operation of block 15 will occur at negative angles 5 when it becomes equal to C, .. In the 8-s plane (Fig. 2) this will correspond to point D. The angle value 5ddl of this point according to the formula Si,) The output signal of the block 15 will exist for all values of the angle D lying to the right of point D, and for s X - to the right of direct AD. At s 0, the operation of block 15 will occur at smaller negative angles of 5, since U 0, and acts in the direction of the failure of block 15. The region of operation of the block will be limited by direct DC, the slope of the coyur is determined by the factor Kg. s and 5 o slip s is determined. -k-h Thus, the output signal of block 15 will exist at ratios between 5 and S, defined by the region lying to the right and above the ADC. Taking into account that the output signals of blocks 15 and 14 act through element 16 I, the response characteristic of the synchronization control body as a whole will look like a parallelogram ABCD. In the zone of operation of the ocean, the conditions V t-- | -, e are met with si-O (0 Thus, for the operation of the proposed ocean, it is necessary and sufficient that at the time of the start signal from the AR unit the angle 5 and the slip s are in specified range of operation. The response time of the proposed ACS is determined practically without the time required to obtain a voltage proportional to the angle and slip and takes several periods. The economic efficiency of the proposed invention is to reduce the damage caused by an electrical break reductions due to the reduction of the dead time during automatic recloser control with synchronization. Claim of the invention Synchronism control authority during automatic re-activation of a power line equipped with a voltage transformer and an automatic reclosing unit and connected to the substation buses, also equipped with a voltage transformer containing a phase shift unit, two - the inputs of which are intended to be connected to the line voltage transformers and busbars, respectively, the first output of the phase shift block is connected to the input of the slip block, and the second output is the first input of the first adder, the output of which through the first threshold unit is connected to the first input of the element I, the second input and output of which are intended to be connected to the first output and the enable input of the ARC unit, respectively, characterized in that in order to increase speed and reliability by ensuring operation at small slips, the first and second detectors, the second adder and the threshold block are entered into it, the second output of the phase shift block is connected to the first input of the second adder, the output of the block is slip through the first and second detectors connected with the second inputs, respectively, of the first and second adders, the output of the second adder through the second threshold unit is connected to the third input of the element I. Sources of information taken into account during the examination 1. Bogorad AM, Nazarov Yu. G. Automatic reclosing in power systems M., “Energie, 1969, p. 336, p. 146. 2. USSR author's certificate for application number 2455362 / 24-07, cl. H 02 H 3/06, 1977. 3. Development of auto-synchronizer ASPU and advanced automatic reclosing device with synchronism trapping, part 2. Report on research work. Theme number 211/71, MEI, 1972.