SU1471246A1 - Device for operating mode control of a mains sections - Google Patents

Abstract

This invention relates to the field of electrical engineering. The purpose of the invention is to improve the quality of voltage regulation in the electrical network section due to the selectivity of switching reactors. Selectivity is achieved by the fact that the devices installed in each node of the networks control not only their voltage (U _I ), but also the voltage in adjacent nodes (U _J ). Provided (U _I –U ^MAX ) * 98 (U _J –U ^max ) (1), or (U _I –U ^MIN ) * 98 (U _J –U ^MIN ) (2), where U ^MAX , U ^MIN , U ^MAX , U ^{MIN - the} maximum allowable levels of monitored voltages, the device switches shunt reactors in "its" node with a shorter time delay (Τ _I1 ). If conditions (1) or (2) are not fulfilled, the switching of reactors is made with a longer delay time (Τ _I2 * 98t _I1 ). At the same time, the time delays in the individual nodes of the network section are chosen different (Τ _I1 ≠ Τ _J1 and Τ _I2 ≠ Τ _J2 ). In this way, voltage overshoot due to the simultaneous switching of several reactors in different network nodes is prevented and the associated possibility of the creation of a self-oscillatory mode. 1 il.

Description

The invention relates to electrical engineering and is used to regulate voltage and reactive power in a portion of an electrical network.

The purpose of the invention is to improve the quality of voltage regulation in the electrical network section due to the selectivity of switching reactors.

The drawing shows a block diagram of the proposed device for controlling the operation mode of a portion of the electrical network.

The electrical network includes several substations 1.2, interconnected by power lines 3. Switching shunt reactors 4, continuously adjustable reactive power compensation units 5 are installed at the substations, the role of which can be performed by synchronous machines with automatic excitation regulators, statistical thyristor compensators with their own automatic voltage regulators or shunt reactors.

tsD

ABOUT

connected to the secondary side of a transformer with an on-load tap-changer equipped with a regulator of nanometer.

The device includes a reactor control circuit 6, a transformer 7 at the substation busbar, a sensor 8 loads of an adjustable reactive power compensation unit, reactor switching units 9 and 10, each of which is made in the form of two comparison elements (9.1, 9.2, 10.1 and 10.2 ) a mode parameter (Q and U), respectively, with maximum and minimum settings, a functional converter I1 of active and reactive power into a signal that fixes the marginal reserves of transmission capacity under the terms of reliability, threshold element nt 12 at the output of the functional converter 1 1, logical elements OR 13-16, logical element AND 17, comparison block 18, elements 1.9-22 of the time lid, relay 23 and 24, ventilation 25 and 26, comparators 27 and 28, adders 29 and 30, the busbar voltage sensor 31 of the adjacent substation, the sensors of the active 32 and reactive 33-power of the power line 3.

Input Switch on the reactor control circuit 6 is connected to the output of the logic element OR 15 whose two inputs are connected to the outputs of the elements 19 and 20 of the time lag, the inputs of the elements 19 and 20 are connected respectively via a disconnecting 23. and the closing 23.2 contacts of the relay 23 with the outputs of the logic element OR 13, the two inputs of the latter are connected to the outputs Turn on the blocks 9 and 21 of the switching reactors.

The input of the reactor switching unit 9 is connected to the load sensor 8 of the adjustable reactive power compensation unit and the input of the unit 10 to the transformer 7 of substation busbar voltage.

Output Turn off the reactor control circuit 6 is connected to the output of an OR 16 logic element, two inputs of which are connected to the outputs of time delay elements 21 and 22, and their inputs, respectively, through a 24 J breakout and a short 24.2 contact of the relay 24 17. One of the two inputs of the element 17 is connected to the output of the logic element OR 14,

two inputs of which are connected to outputs Switch off reactors 9 and 10, and the third r with the output of threshold element 12 installed at the output of functional converter 1 1. Two inputs of funcion converter 1 1 are connected to sensors of active 32 and reactive 33 power lines 3 power lines.

The second input of the logic element AND 1 7 is connected to the output of the comparison unit 18, the input of which is connected to the output of the difference of the comparison element included in the reactor switching unit 10.

The winding of the relay 23 through the positive polarity valve 25 is connected to the output of a comparator 27 installed at the output of the adder 29, one of the inputs of which is connected to the transformer 7 of the busbar voltage substation. second, with sensor 31, the tire voltage of the adjacent substation.

The winding of the relay 24 is connected via a negative polarity valve to the output of a comparator 28 installed at the output of the adder 30, whose two inputs are also connected to a voltage transformer 7 and a voltage sensor 31.

The proposed device is installed at several substations of the controlled section of the electrical network, in particular at electrically close power facilities, and is intended for operation in all normal operating conditions, which are characterized by a change in a wide range of power flows along the transmission lines connecting these substations.

Simultaneously with the change of the load of the power transmission line 3 under the influence of automatic voltage regulators included in the reactive power compensation blocks 5 installed at the substations, the load of the latter changes, as well as the voltage levels on the substation buses, as its regulation is performed with a certain statistics. depending both on us-three of the indicated regulators (statism, installation, on voltage), and on the circuit of connecting the sources of reactive power to the substation buses (directly or through obvious resistance).

In this case, both the exhaustive control of the adjustment ranges of the installed at the substations, adjustable blocks, reactive power compensation, and the achievement of maximum permissible voltage levels at the substation buses can occur. The release of the specified adjustment ranges with simultaneous return of the voltage levels on the buses of substations to the allowable limits is achieved by switching shunt reactors 4.

Since the listed violations of the permissible mode can occur simultaneously at several substations, for example, during abrupt changes in power flow along transmission lines, switching shunt networks: more unit power simultaneously at several substations according to this factor can lead to overshoot and the occurrence of the auto-oscillatory mode. with alternate on-off these reactors. On the other hand, due to the electrical proximity of replaceable substations of the considered network area, it may be sufficient to switch only one shunt reactor at one substation,

The device works as follows.

Blocks 9 and 1 of the switching reactors and functional converter 11 control the load (O) of the reactive power compensation unit 5, the voltage level on the tires 1 and the load of the power transmission line 3 and generate the Enable or Disable next shunt reactor commands. At the same time, the inputs of the adders 29 and 30 receive the voltage of the tires of this substation W and the tires of the adjacent substation Tsg. (the last with the sign -) and corrective amendments of the Mox mchn

The signals at the outputs of adders 29 and 30 are respectively

whether

mox

tt tt vmax / ,, t, maxch U-UgTc - (. U / I) - (U, +

.A and

min

 and, - and, (and, - iG) - (i - Ue) -,

Where

 and.

- and.

+1

- ah 6

summn. - corrective amendments, taking into account the difference in the boundary values of voltages at adjacent substations J Si - on-° setting parameter.

The switches 27 and 28 at the output of the adders 29 and 30 form normalized signals, the polarity of which

.- is determined by the polarity of the signals of the signals d, respectively.

With di 0, valves 25 and 26 remain closed; relays 23 and 24 are de-energized, and the commands

15 Turn on and Turn off, produced by blocks 9-11, are fed to the corresponding inputs of the reactor control circuit 6 through the closed contacts 23.1 and 24.1 and the elements 19

20 and 21 times of T1, TZ time, implementing minimal time delays (in a particular case. T1 TZ 0 can be accepted)

If ip oh

25, respectively, open valves 25 and 26 and relays 23 and 24 switch their contacts. This leads to the fact that the specified commands Enable - Disable arrive at

30 inputs of the reactor control circuit 6 after 20 and 22 times of time T2 and T4 implementing a large delay (T2 T1 and)

Srabatshan relay 23 and 24 under the conditions of O or O is provided by the choice of the value of the tuning parameter.

The busbar voltage of the adjacent substation is postloaded to the inputs of adders 29 and 30 from the output of sensor 31, which can be either a telemechanical sensor or a functional converter of the tire center ICR of the given substation I, active and reactive power of the power line 3, to the voltage across Tires adjacent substation 2, for example, according to the formula

-tt - I / Pi - 10h - Ut (b ,, - b.) f

and. - - I /,

where pj and

Qj - active and reactive power of power line 3,

be is the transverse conductivity in the U-shaped replacement circuit of line 3 at substation bus 1,

YS and bj, respectively, the modulus of the longitudinal conductivity and the reactive component of the longitudinal conductivity of line 3 in the U-shaped replacement circuit.

If it is necessary to control a section of electric web that covers several adjacent substations, additional sensors 31 on the number of adjacent substations and associated chains-elements 29, 27, 25 and 30, 28, 26 with their connection to the windings of the relay must be entered into the device. 23 and 24 respectively. However, this increase in the elements in the proposed device does not change the principle of its operation.

Claims (1)

Invention Formula A device for controlling the operation mode of an electrical network section of substations connected to a power line with reactors and adjustable reactive power compensation blocks, containing a reactor control circuit, a substation busbar voltage transformer, a reactive power compensation block load sensor, and an active and reactive functional converter power in the signal, fixing the marginal reserves of transmission capacity under the terms of reliability, the threshold element output a functional converter, two switchgears of reactors, each executed in the form of two comparison elements with a maximum and minimum setpoint, a comparison block, two logical elements OR, an AND logic element and sensors of active and reaction power of the transmission line connected to the inputs of the functional converter, output which through the threshold element and the first logical element OR is connected to the input of the element AND, A load sensor of an adjustable re-active power compensation unit is connected to the second input of the first OR element and the second OR input to the second switching unit of the reactor; the transformer substation voltage transformer is connected to the third input of the first OR element through the second switching unit of the reactors OR and the second the input of the second element OR, the output of the difference element comparing with the maximum setpoint, the second reactor switching unit through the comparison unit is connected with the second input of the element I, which is due to the fact that in order to improve the quality of voltage regulation on the electrical network section due to the selectivity of switching reactors, a tire voltage sensor of an adjacent substation, two adders, two comparators, two ventilators , two relays, four time delay elements, the third and fourth logical elements OR, and the input Enable reactor control circuits through the third OR element connected to the outputs of the first and second time delay elements whose inputs are connected respectively Via the closed and open contacts of the first relay with the output of the second element OR, the input Disconnect the reactor control circuits through the fourth element OR connected to the outputs of the third and fourth time delay elements, the inputs of which are connected respectively through the closed and open contacts of the second relay to the output of the element I, winding the first relay through the positive polarity valve, the first comparator and the first adder, and the winding of the second relay through the negative polarity valve, the second comparator and the second with adder, connected to transformer busbars of the substation, the second inputs of the adders are connected to the voltage sensor of the adjacent substation of -And he lET ir Ib.xbi r