SU120584A1 - Device for automatic control of electric generator braking in violation of the dynamic stability of its work - Google Patents

Description

The proposed device for automatic control of the TopNio electric generator in violation of the dynamic stability of its operation refers to a known type of devices of the same purpose, consisting of a speed sensor in the form of a tachoxyerator, lightly coupled to the shaft of the main generator, a filter for smoothing the pulsations of the latter, element 1ta, revealing a violation of stability, amplifier and executive relay circuit.

The main feature of the device is the use of a GE as an element that detects a disturbance in generator stability. e% of the bone-ohmic circuit, the output voltage of which is proportional to the first derivative of the increment of the angle between the emf vector the generator and the system voltage, is supplied to the input of the executive relay circuit that controls the torch resistance switch (.

The control of braking, depending on the magnitude and sign of the increment of the specified angle along its first derivative, increases the dynamic stability of the generator.

The executive relay circuit of the proposed device provides for the use of two polarized relays, the first of which is triggered by increasing the voltage on the capacitive-ohmic circuit to a predetermined value} P1 and prepares the power supply circuit of the second polarized relay used to turn on the output relay closing the brake resistance switch. the execution of the relay actuator circuit makes it possible to detect the need for braking when

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the derivative of the angle is positive, and also the termination of the brake when the derivative of this derivative passes through zero. fng 1 shows a block diagram of the proposed device; in fig. 2 is a diagram of an element that reveals a violation of generator stability; in fig. 3 - Executive relay circuit B The structure of the proposed device includes the following main components: a TG tachoheiyerator rigidly articulated with the main generator SG shaft, a filter F, a representative element B, an amplifier V and an executive relay circuit P.

The TG tachogenerator, designed to measure the rotational speed of the main generator, can be made in the form of a DC machine or an AC machine with a rectifier of any type.

Filter Φ serves to smooth the pulsations of the tachoheiyerator voltage caused by the jagged harmonics, the potential eccentricity of the rotor, and so on.

The critical element B is designed to detect the deviation of the rotational speed of the generator from the synchronous one. (1: s), is an RC capacitive-ohmic circuit with a constant time of about 2-5 seconds. (Fig. 2), In steady state, the voltage of the capacitor C is equal to the voltage U of the tachogenerator, and the voltage O ;. The input voltage of the amplifier Y is zero. When the speed deviates from the amplifier established at the input, a voltage equal to the difference between the tachogenerator voltage at the current time of the current and the voltage that occurred in the previous accident mode is applied. Thus, capacitance C in this case plays the role of an element that memorizes the nature of the regime that preceded the emergency one. Since braking is performed once, the capacitance must be kept in memory the previous voltage value of the tachogenerator to the first maximum of the generator angle, which determines the time constant of the circuit. If repeated braking is required, the time constant increases accordingly.

As an amplifier Y, both electronic and magnetic amplifiers assembled according to known circuits can be used. The magnitude of the gain is selected depending on the magnitude of the voltage supplied by the detection element, i.e. the magnitude of the nominal voltage of the tachogenerator. The executive relay circuit, directly controlling the braking, consists of a blocking relay -P - /, selective fields relays R-2 and R-3 and executive intermediate relay R-4 (Fig. 3).

The switching on and off of braking is carried out by closing and opening the normally open contacts of relay R-4. These contacts are used to control the coil of a switch or other actuator.

Election relay R-2 has two windings (working and additional) and responds to a positive input voltage, i.e., to the value of the first derivative of the angle increment, i have a positive sign. The setting of this relay is varied by variable resistance R.

The selective relay P-3 reacts to a positive value of the angle of the D-J angle b. The voltage, proportional to D c, is removed from the capacitor Cc, which, together with the resistance, constitutes an integrating circuit. The sensitivity of the relay P-3, i.e. the setting in accordance with D 6, is changed by the variable resistance Rz.

in the steady-state pre-emergency mode, the speed has increased ;; -; The jueir of the geerator is constant, the stress is tachogen1) ator 6- - canxi, ;;;. The voltage at the input and output of the amplifier is equal to zero, the contacts i; are in the position shown in fig. 3

With an increase in the rotational speed of a geyerator caused by a nanr: short circuit, the voltage of the tachogenerator increases and the output voltage of the output element appears, npo ;; opiuicual derivative of the angle angle. This voltage after amplification goes to the input of the circuit.

The selective relay P-2 monitors the magnitude of the derived angle and is triggered by increasing it to a predetermined value. Trigger, this is a relay through normally closed contacts of the blocking relay P- / gives “plus to the contacts of the electoral relay P-3 and one Bremen; ; about another pair of contacts shunts the resistance of the RI, thereby increasing its sensitivity.

At the moment when the angle of the corner reaches the specified value, the selective relay R-3 closes its contacts, as a result of which the plus hits the coil of the executive relay P-4 on the next, triggers, causes the short circuit switch VT of the brake resistance of the Hg (fig. 1) to close. )

Braking lasts until the angle has reached the maximum value. At this moment, the derivative of the angle becomes paBiioii zero, i.e. the zero input voltage becomes executive; relay circuit, as a result of which the relay P-2 releases its contacts, the power supply circuit of the relay P-4 is broken and the braking 1e is stopped. At the same time, the second pair of contacts of relay P-2 opens the resistance RI and returns its sensitivity (setpoint) to the initial value. Contact and relay R-2, returning to its outcome (the voltage on its working winding, which changes its sign, also contributes to this), supplies power to an additional € 2 capacitor and resistor Rt, as a result of which the relay P -2 ca is deducted for a time, depending on the constant charging time of the capacitor Cr, thus ensuring a one-time braking during a given accident. After a predetermined period of time, the charge of the capacitor C- is stopped and relay P-2 regains its ability to work. The capacitor C2 is discharged through the resistance Rs with the turn of 0 m. The relay R-4 trips. If it is necessary to brake for several times during the swinging process, the switch B should be open. In this case, when alternating generator acceleration (if this acceleration may be dangerous, i.e., if the voltage at the input of the relay circuit again sets relay P-2), the braking cycle will repeat.

In the event of an unforeseen severe accident, when, despite the Bkl, a reading is inhibited and. the angle in increases infinitely and stability is violated, automatic braking of 1 is provided by means of the blocking relay P-1, having a delay time P defined by the constant circuit Cs-RS- If the duration of the brake 1 exceeds the limit value, the relay P-1 is activated and removes from the executive relay R-4, as a result of which the braking stops. Relay P-1 switches on self-holding when using its normally open contacts.

After the restoration of the parallel operation of the generator, the device is re-enabled by the duty personnel manually using the key Ki. First you need to make sure

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In the current mode (voltage at the input of a pseudo-relay circuit), using the pointer zero, the selective organs and the full relay circuit can also be executed on the thyratrons. In this case, the setpoint is changed; By correspondingly changing the constant of the 10th displacement on the grids of the thyratrons. Simultaneously with the braking control, the proposed device allows one to additionally control the generator excitation force, forcibly tightening it in the first cycle of oscillations until the generator angle maximum. For this purpose, the P-4 relay also adds another pair of normally open contacts, through which an EF signal is supplied for relay forcing the excitation of the SG generator (Fig. 1). It can also be used to control the excitation of a generator with the participation of the first and second derivatives of the angle H without telemetry. To do this, we use the voltage from the amplifier output - By applying this voltage RV (Fig. 1) directly to the input of the electronic excitation controller (through a divider providing the appropriate gain factor), we obtain a control channel along the in, additional differentiation of the voltage from the amplifier output gives channel in

The subject is invented and

Claims (2)

1. A device for automatically controlling the deceleration of an electric generator when the dynamic stability of its operation is disturbed, consisting of a speed sensor in the form of a tachoger, rigidly coupled to the shaft of the main generator, a filter for smoothing the ripple voltage of the low-voltage element that exhibits stability violation, An amplifier and an executive relay circuit, characterized in that, in order to control the braking depending on the magnitude and sign of the increment of the angle 0 between the emf vector. the generator and the system voltage according to its primary derivative, as a component that detects the disturbance of the generator stability, a capacitance-ohmic circuit is applied, the output voltage of which is proportional to the first derivative of the angle increment b, is fed to the input of the executive relay circuit that controls the brake switch resistances. 2. The device according to p-1, characterized in that, in order to identify the need for braking when the derivative angle reaches a positive value, as well as the end of braking when this derivative passes through a zero value, two polarized relays are used in the executive relay circuit, The first of which is triggered by increasing the voltage on the capacitive-ohmic circuit to a predetermined value and prepares the power supply circuit of the second polarized relay, which serves to turn on the output relay, closing brake switch resistances 3. The device according to PP. 1 and 2, characterized in that, in order to stop braking in case of severe accidents, when switching on the braking resistors does not stop the angle rise, an interlocking relay is applied in the executive relay circuit that operates with a predetermined time delay and breaks the power supply circuit of the polarized relays. 4. Application in the device according to claims. 1-3 as a low-power alternator alternator speed sensor with rectifier PB jj oh I ./a Sxod booster ABOUT