SU1737625A1 - Device for automatic turn-on of stand-by supply of consumers with motor load - Google Patents

Description

no switches of the main and backup inputs and the inclusion of the section switch, the first 23 and the second 24 bus sections.

Switches 3 and 4 are normally on, 5 is off.

Blocks 10 and 11 are connected to the same linear voltages of the phases of the first and second bus sections (for example, UAB), and blocks 8 and 9 are connected to the phase current (-1V) of the main and backup inputs. The blocks 14,12,16,18 form the measuring phase-sensitive organ of the first channel IF01, and the blocks 15,13,17,19 form the measuring phase-sensitive organ of the second channel IF02, which are identical to each other.

In the absence of current and the presence of phase-matching voltages Ui and U2, the measuring phase-sensitive organ performs the functions of a minimum voltage relay with a trigger condition for the effective voltage values

ten

,

(2)

Ka

where -.t is the ratio of the coefficients of (1),

which can be adjusted in the range from 0.2 to 0.8 by changing the magnitude of the active resistances in blocks 14 and 15.

At the outputs of the blocks 14,16,15,17, the voltages E1, E2, E3, E4, respectively, are formed, each of which is a linear function of the input currents and voltages: 20

Ei KiUi-K202 + K3il Ё2 K4U2 Oz K4U1

E4 KlLJ2-K2Ul + K3l2

where Ki, K2, Kz are real proportionality coefficients at voltages and currents depending on the input active resistances in adders 14 and 15;

Cd is the complex coefficient of proportionality under voltage, providing an internal phase shift during the formation of E2 and E4 voltages by an angle of / 30 due to the phase-turning differentiating RC-chain in blocks 12 and 13;

O is the voltage of the first section (for example, (UABI);

Og - voltage of the second section (for example,. UABII);

ji is the current of the first input (for example, -1VO;

12 - the current of the second input (for example, -1VK).

Block 18 compares the Phase E1 and E2 in phase, and Block 19 compares E3 and E4. These blocks are triggered if the difference angle between the compared values of y is greater than the specified one, for example, y 1.

In normal mode, a resistive load in the presence of symmetric voltages of the main and backup sources of nominal magnitude, the current leads the UAB voltage by an angle of 30. As the phase shift in the current circuit is compensated by the phase shift in the voltage circuit (in blocks 12 or 13), the measuring voltage the phase sensitive organ responds to a change in the direction of the active power with an angle of maximum sensitivity of 180 ° and a certain response current.

20

25

thirty

35

If U2 UH is 100 V, then the Lhcp trigger voltage can be adjusted from 20 to 80 V.

When the power supply of the first busbar section is lost (i.e., at H 0), the synchronous motors connected to this section go to the generator mode and maintain a damped voltage of decreasing frequency on the section. In this case, the voltage Oj begins to lag in phase relative to U2, which leads to the lagging of the vector E1 relative to E2, which are compared in phase in the first IFO (Fig. 3a). At the goal, the 1 discrepancy between the values of Ё1 and Е2 is equal to

yi 5hi + 5i + ai,

(3)

where b n1 30 ° - the initial angle of divergence of the values of E2 and U2, due to an internal shift in the IFO (i.e. in block 12);

d is the lagging angle of the voltage Ui relative to the voltage U2,

a is the angle of additional shift caused by the effect of the vector

Yb

On the verge of triggering the first IFO at 1 90 °, and d 1 + a 1 60 °. Since when ui

and 1СР arcsln (-) arcsln (j 0,866), then d 1СР - 60 - arcsln (- 0,866), hail, (4)

where Uyt - Y is the voltage setting

operation of the first IFO, adjustable in the range of 20-80 V.

The values of the angles a icp and 6 1cp, depending on the setting of the first IFO for the response voltage, are given in the table.

When the power supply of the first busbar section is lost, the first IFO triggers earlier than the second IFO, and block 20 provides the first output, when through block 21 the switch 3 is turned off and the switch 5 is then turned off from the contact contacts. The switch 3 is turned on. It is also possible with the control from the BCS in-phase control unit (if available), which eliminates the antiphase activation of synchronous motors in the case of a slow shutdown of the switch 3.

When the second section of the bus loses power, the voltage U2 begins to lag in phase relative to .LH, which leads to lagging of vector E4 relative to E 3 (fig.zb), compared in phase in the second IFO, Angle 2 is the difference of E4 and E.3 2 5n2 + 5 2 + 2 2 (5), where dn2 30 ° is the initial angle of divergence between Ј3 and SI, due to an internal shift in the IFO (i.e. in block 13):

 fa. Angle of lagging voltage IJ2 relative to voltage Ui;

03. - the angle of the additional shift due to the influence of the vector

-ЈOn the verge of the second IFO U 2 90 °, and b 2 + 2 60 °. Since when ui

"2cp arcsin (0.866), 40

b 2cP 60 - arcsln (j & - 0.866), deg (6)

that

where uy2

K2 Ki

100 - voltage setting

operation of the second IFO, adjustable in the range of 20-80 V.

The values of the angles a 2cp and g 2cp depending on the setting of the second IFO for the response voltage are given in the table.

If the second bus’s lithium is lost, the second IFO bus triggered earlier than the first IFO, and block 20 provides operation on the second output, when through block 22

5 10 15

20 5

0

five

0

five

0

five

Switching off the switch 4 and then turning on the switch 5 in the same way as described above is made.

Claims (1)

The invention device for automatic switching on backup power supply with motor load, containing the first and second intermediate voltage transformers with direct and inverse outputs, the inputs of which are connected to the outputs of the measuring voltage transformers of the sections of busbars of the main and backup sources, section switch connected between sections, the first and second intermediate current transformers connected respectively to the main and standby current transformers inputs, the first and second adders with three inputs, the first inputs of which are connected respectively to the direct outputs of the first and second intermediate voltage transformers, the second inputs to the outputs of the first and second intermediate current transformers, the third inputs to the inverse outputs of the second and first intermediate voltage transformers, the first and second amplifiers, the first phase comparison unit, the inputs of which are connected to the outputs of the first adder and amplifier, the second phase comparison unit, the inputs of which are connected to the outputs of the second of the adder and amplifier, the first and second control units by turning off the main and backup switches, respectively, of the inputs and switching on the sectional switch, from which, in order to increase the selectivity and speed, the first and second phase-turning differentiating RC-blocks were introduced, the detection unit operation priorities with two inputs and two outputs, with the inputs of the first and second phase-turning units connected to the direct outputs of the second and first intermediate transformers respectively and the outputs of these blocks are connected to the inputs of the first and second amplifiers, the first and second inputs of the priority detection unit are connected to the outputs of the first and second phase comparison units, and the first and second outputs of the priority detection unit are connected to the inputs of the first and second blocks management Phie.1 R Ar./I ti 1J FIG. 2 L