SU1327229A1 - Method of automatic starting and self=starting of electric motors in emergency conditions - Google Patents

Abstract

The invention relates to the field of power engineering and is intended for the automatic control of the start-up and self-start of large electric motors in the load nodes of the power system equipped with emergency control devices. The goal is to increase the reliability of the node’s electrical power supply by reducing the risk of damage to the motors during their start-up and self-starting. During system automation, which led to the disconnection of a part of consumers, but not requiring switching to a backup power source, voltage is supplied to the input of blocks 3 and 4 the voltage of the switchgear sections in the postemergency mode. If it is less than the maximum setting, but more than the minimum, signals are sent to the inputs of the imaging unit 7. To the other input of the imager a signal is received from technological automation. The control circuit drives the motors in the specified sequence. Depending on the signal level from block 6, according to the pre-calculated modes, block 8 selects the working motors for their transfer to asynchronous mode. 2 Il. cl

Description

one,

The invention relates to power engineering and is intended for automatic control of the start-up and amostart of large electric motors in the load nodes of the power system equipped with emergency control devices.

The purpose of the invention is to improve the reliability of the power supply to the load unit by reducing the risk of damage to the engines during their start-up and self-starting.

Figure 1 shows a variant of the functional diagram of the device that implements t o the proposed method, in FIG. 2 illustrates an embodiment of an engine selection unit for translating them into an asynchronous mode, comprising a set of comparators corresponding to the number of engines, and an I-type logic actuator.

The device for automatic start and self-starting of electric motors contains the unit 1 for measuring the magnitude and the unit 2 for the phase voltage of the switchgear sections of the consumers, the blocks 3, 4 and 5 of the level comparison, MIM ,, m "" s

voltage and set -jCT - switch-on angle with settings unit 6 controlling the magnitude and direction of the active power of electric motors operating from controlled switchgear sections, driver 7 triggering signals, a logical element And, and block 8 motors for converting them to asynchronous mode.

The inputs of the magnitude measurement unit 1, the voltage phase measurement unit 2 and the magnitude and direction control unit 6 of the active power are supplied to the voltage of the switchgear sections (e.g., C and U) of the load node. The currents of the sections (1 and I ,,) are additionally supplied to the inputs of block 6. The output of block 1 is connected to the inputs of block 3 and 4 of the comparison, the output of block 2 is connected to the input of block 5, and the outputs of block 6 are connected to the input of block 8 of choice and the input of block 7 of the driver. The other input of block 8 is connected to the output of comparator block 4, and the outputs of blocks 3 and 5 are connected to the corresponding inputs of block 7, the outputs of blocks 7 and 8 are included in the engine control circuit.

2292

The Ffa output of the comparison unit 3 signal appears only when the voltage section of the maximum setpoint Uycr is exceeded) is usually in the range of values (0.85-0.9). At the output of the comparison unit 5, a signal appears only at the angle θ between the stress vectors of the sections and and and, located in the angle range of c / - sec / 2 specified by the condition of admissible asynchronous switching on (inputs 2, 3 of block 5) . The signal from the 2nd output of the control unit 6 of the magnitude and direction of the active power occurs only when the direction of the active power is changed in the direction of its transfer to the network. The signal from the output 2 of the block 4 compared with the run / (T T ti MCtKC (Uj) r and yg is fed to the input 2 of the block 7 of the driver trigger signal, which is a logical element And, and when the condition U (Uj) U 7 is fulfilled output 1 of block 4 comparison - to-ln input of block 8 for selecting the volume of the number of operating motors for switching to asynchronous mode. To another input of block 8 a signal is sent to monitor the magnitude of active power from output 1 of block 6. Driving signal generator 7 is connected by input 5 s technological automation load requiring, for example , Activate or deactivate the motor when changing the performance mechanisms.

In emergency mode, in the power system associated with the operation of the system automation, leading to the disconnection of a part of the consumers, but not requiring switching to a backup power source, the input voltage of the units 3 and 4 of the voltage level comparison is supplied and voltage or Uj on the distribution sections devices in the postemergency mode, measured in block 1. In the case

.. WC KTTMII

if it is smaller and t, but greater than U, the signals from the comparison units 3 and 4 are fed to the corresponding inputs of the driver 7 triggering signals, which in turn receive a signal from the technological automation that predetermines the switching sequence of the electric motors of the required mechanisms. The signal obtained from this data in block 7 of the driver of trigger signals goes to the motor control circuit, which turns on the switches of these mechanisms.

If the voltage at the input of the unit 4

more than that.

And the signal arrives at block 8 for selecting the volume of the number of operating motors for transferring them to asynchronous mode. For operation of block 8, information is needed on the amount of active power of the operating engines, which is fed to its other input from output 2 of block 6, controlling the magnitude and direction of the active power. Depending on the level of the signal from block 6 and with vypolTT / Y MLKS

According to the pre-calculated modes, unit 8 selects the working motors for their transfer to asynchronous mode.

For example, when the voltage increases above the setpoint of the comparator 9 (FIG. 2, a high logic level signal is generated at its output, which arrives at the input of the AND 10 logic element and if there is a second input at its second input

tension

.C f

lower and VCT input

35

the signal from block 6 from the output of the circuit AND 10 25 from the output of block 6 on the magnitude of the active signal to shut off the excitation of the first engine. As the voltage increases above the set point of the comparator 11, a high logic level signal is generated at its input, Go (Arriving at the third input of an AND 12 logic element, the first input of which receives a high level signal from the comparator 9, and the second input - the signal from block 6. In this case, at the output of the element And 12, a signal is generated to shut off the excitation of the second engine, i.e., two engines will be disconnected. Block 8 works in the same way, turning off all n engines in case of need. Thus, the signal from block 8 enters the motor control circuit, which cuts off the excitation of selected engines, closes their excitation windings to damping resistance and when the voltage level C decreases, or U on the busbars of switchgear sections below

engine power. The signal from block 8 enters the motor control circuit, which turns off the excitation of the selected ones. motors of the working section, closes their OB by damping resistance when the levels of the working section below and V, CT of the unit 4 decrease) in the sequence described above, the section switch is turned on between the working section and the section that lost power.

Claims (1)

Invention Formula 45 The signal from the output of measurement unit 4 is fed to the input of the generator unit 7 in accordance with the signal level before the input in the sequence described above, the required mechanisms are activated by the input signal from block 7. If the emergency mode is connected with the loss of power of one of the sections of the automatic start and the motor starting up in emergency modes of the load node of the power system, in which, in case of accidents connected with the loss of power by the signals of the automatic emergency automation, a part of the electric motors is turned off determined by the controlled parameters of the pre-emergency mode, and start the electric motors, besides restoring the voltage, characterized in that, in order to increase the reliability of the power supply of the load node, spine injury motor during starting and self-starting, when the voltage on prevsh1enii section maximum allowable under the conditions of start values are converted 50 but 1327229 distribution devices, the phase angle c / between the measured 0 five 0 unit 2, voltage mi and u., and a signal proportional to it, is fed to the input of unit 5 of the comparison. When condition Y is fulfilled (set by one input of block 5): c / (/ (set by another input of block 5), its output is a signal that goes to input of block 7. If one of the sections loses power and the direction changes The power from the motor output appears from the output of block 6, which is fed to the input of block 7 of forming signals. If at block 4 the comparison of the voltage of the section that does not lose power is greater (input of block 4), then the signal from the output byyoka 4 is fed to the input of the engine size selection unit 8 for their transfer to the asynchronous mode by pre-calculated modes, also taking into account information on the signal from voltage on shimo k. c f lower and VCT input the output of block 6 on the value of the active engine power. The signal from block 8 enters the motor control circuit, which turns off the excitation of the selected ones. motors of the working section, closes their OB with damping resistance and when the working section levels below and V, CT of block 4 decrease), in the sequence described above, the section switch is turned on between the working section and the section that lost power. Invention Formula 25 outputs of block 6 on the value of the active Q 0 45 The method of automatic start-up and self-starting of electric motors in emergency mode of the load node of the power system, in which, in case of accidents associated with loss of power by signals from emergency automation, disconnect part of the electric motors in an amount determined by controlled parameters of the pre-emergency mode and start the electric motors except for restoring characterized in that, in order to increase the reliability of the power supply of the load node by reducing the risk of damage to the electric motors during start-up, Starting PC at prevsh1enii voltage at the section of maximum permissible conditions pickup value converted 50 513272296 a part of the non-switched electric motors, the values are resynchronized by the electric motors into the asynchronous mode, after decreasing, the gatelles transferred into the asynchronous voltage on the sections to the permissible mode. f yClTlj From block 6 Off.6to5. J-eo CM Off Dozb. 2-80 cm Off. 3rd CM  Off, 9h5, goSM § Oq FIG. 2 Editor A.Dolinich Compiled by G. Damska Tehred V. Kadar Order 3405/52. Circulation 617 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., d. A / 5 Production and printing company, Uzhgorod, st. Project, 4 Proofreader V. But ha