SU746803A1 - Voltage monitoring device - Google Patents

Description

The invention relates to relay protection, in particular, to emergency control devices, and can be used to detect the undervoltage of three and two phase arc short circuits, phase failure in AC networks, especially in ship power systems. A undervoltage detection device is known, which contains a three-phase, full-phase measuring bridge, to the output of which a voltage divider is connected via a U-shaped RC filter, and a voltage source is connected to the voltage divider by one output through a separating diode, the second one through a magnetic control winding ussighel 0-3. However, there is a lack of fast action and limited functionality arising in connection with the npi change of the P – F – phttra of the magnetic force of the body. Closest to the offer, in its technical essence, there is a voltage control device containing a three-phase one-pin driver rectifier with a voltage divider to which the first transistor capacitor with capacitor is connected via a threshold element. A second transistor switch with a capacitive filter is connected to the first transistor switch (2}. Use in the device width (- the pulse comparison principle allows to slightly increase the speed of the device and expand its functionality). high-speed automation systems, as it has insufficient speed and limited functionality due to the use of single-period c we measure and shirof but pulse Oakham sfavneav.

746803

The goal of reversal is to increase the speed and expansion of the soul capacity of the device.

Goal Achieved by the fact that in a voltage monitoring device containing a measuring gel, a divider is connected to the output, a first transistor switch with a capacitor is connected to the divider through a threshold element, and a second transistor switch is connected to the divider through an additional threshold element As the Larionov bridge, the displacement circuit is connected to the base of the first key switch transistor, and the meter and yorog element are switched inversely. FIG. 1 shows a priytsipialnaya scheme of the described device; Fig. 2 shows the voltage plots on it, where mode A is normal; mode B - mode of low voltage and three-phase short circuit; mode B - two-phase short-circuit mode, and phase failure. - -...-..- -. .-, .. „,., .., The device for controlling voltage contains a meter 1 with a voltage divider 2, to which through a threshold element (Zener diode) 3 is connected the first transistor switch 4 with a capacitance equipped with a bias circuit 5, to the output of which through the additional threshold element (zener diode) b the second transistor is connected}, 1st key 7. The device works as follows. In the normal standby mode, the measured voltage is higher than the voltage of the breakdown of the Zener diode 3, the Zener diode is pierced and the locking voltage is applied to the base of the transistor switch 4. The transistor is closed and the capacitor is charged until the supply voltage of the circuit that is higher than the voltage of the Zener diode 6, The stabilitron is broken and the second transistor switch 7 is open, the output voltage is zero (fig 2, mode A). When the voltage drops below the set value, which is determined by divider 2, or a three-phase short circuit, the measured voltage c anovits less than the breakdown voltage of the zener diode 3. The Zener diode 3 is closed, and the transistor switch 4 is opened bias circuit 5 and kondenoator instantaneously is permitted through the transistor zero. Zener diode 6 is closed and the second TpaH3HCTqpHbiA key 7 is locked, the output voltage is equal to the voltage of the power supply (Fig. 2, mode B).

I 4

In the case of a two-phase short circuit or a phase break, the immersed voltage has the form of a two-phase full-wave (Fig. 2, mode B). At times when the measured voltage is lower than the voltage of the breakdown of Zener diode 3, the first transistor key with capacitance opens and operates in the Open-Closed mode with the frequency of the measured voltage. The key capacitor operates in the ZarDRazr mode also with the frequency of the measured voltage and does not prevent infection before the voltage of the breakdown of the zener diode 6. The zener diode 6 and the second transistor switch 7 remain closed after the first voltage drop (Fig. 2, mode B) , From the voltage diagrams (Fig. 2), it can be seen that due to the use of the Larionov bridge and an additional bias circuit to the base of the first transistor switch as a gauge, as well as the inclusion of the MORITEL} and the threshold element, the device described has chi instantaneous speed, and the use of capacitance in the first transistor switch, allows, without rebuilding the circuit elements, to reveal two-phase and three-phase arc and metal short-circuits, breakage from the phases of the supply voltage, i.e. expand the functionality of the device. When choosing a specific setpoint, the device can serve to detect overvoltage. In addition, the proposed device has an adjustment range of settings from 0 to 88%, while the known device has from 50 to 1OO%. The voltage settings of the emergency control device to detect short-circuit modes. choose the outcome of the detuning from the start-up transition modes in the protected network in the range of 30-80%. To reduce the effects of short-circuits, it is important to detect the short-circuit mode instantaneously. The invention allows detecting emergency conditions of the protected network with sufficient speed: three-phase and two-phase, arc and metal short-circuits, phase failure, reduction and increase in voltage. Using it will significantly reduce damage from accidents and reduce the number of applied protection devices. The effectiveness of using the described low voltage detection device is confirmed exertiously. The formula for voltage control, containing a meter, to the output of which a dalitel is connected, through a threshold element to the divider is connected a first transistor switch with a capacitance to which a second transistor switch is connected through an additional threshold element, in order to increase speed and expand functionality, the meter is made in the form of a Larionov bridge, an additional bias circuit is connected to the base of the first transistor switch, and the meter and the PSD are item included inversely. Sources of information taken into account for the examination 1. Arzhannikov B. A. and others. Modes of operation of the main elements of the circuit of the automatic voltage regulator of a voltage transformer. About. Proceedings of the Ural Electr (Mechanical Institute of the Institute of Railway Transport, issue 24, Sverdlovsas, 1969, p. 39, 2. US Patent No. 3749944, cl. 307-235 H 02 H 3/24, H 03 c, 5/18 1973.

Claims (1)

Claim A voltage monitoring device comprising a meter, to the output of which a divider is connected, through a threshold 5 element, a first transistor switch with a capacitance is connected to the divider, to which a second transistor switch is connected through an additional threshold element, characterized in that, in order to improve performance and expand functionality, the meter is made in the form of a Larionov bridge, an additional bias circuit is switched on, and the meter and the threshold element is inverted.