SU531449A1 - Device for protecting conversion bridge of d.c.pw transmission - Google Patents

Abstract

A DEVICE FOR PROTECTING THE CONVERTER BRANCH OF A POWERING CURRENT ELECTRIC TRANSMISSION, containing a reacting organ, switched on in the bridge rectifier current sensor circuit, various reacting organs included in the sensor circuit of the phase currents, the matching circuits of the phase reactors and included in their response circuit components and their output circuits. OR ", characterized in that, in order to increase reliability, the output of the scheme" ШШ "is connected via an additional inverter matching circuit, the second input of which is connected via another additional inverter and additional A 1 ”circuit” or “is connected to the outputs of the phase reacting organs, and the third input is connected to the output of the reacting organ of the measured current”

Description

The invention relates to the field of electrical engineering and can be used to protect converter bridges of high voltage DC transmissions,

A device for protection of converter bridges of direct current power transmission is known, based on the use of elements of digital

NIKIO

It is also known a device for protecting DC power transmission bridges, containing reacting bodies, included in a bridge current sensor circuit and in a phase current sensor circuit, reacting body signal matching circuits and output:; blocks that are closest to the invention in its technical essence and the achieved result.

Calculation of the reliability of such a device Q

VA showed that the magnitude of his operating time on. Failure of the false bounce type does not satisfy the requirements for the reliability of protection devices for rectifying direct current power bridges, since a false bounce can occur if any of its elements connected before the inputs of the coincidence circuits fail.

The purpose of the invention is to increase the reliability of the device.

The goal is achieved by the fact that in the device containing the reacting organ included in the sensor circuit. of the rectified bridge current, different reacting bodies included in the sensor circuit of the phase currents, the matching circuit of the signals of the phase reacting organs and the circuit connected to their outputs 353 Or, the output circuit of the SRI connects the coincidence circuit, the second input of which is through an additional inverter and additional circuit OR connected to the outputs of the phase reacting organs, and the third input to the output of the reacting body of the rectified current of the signal of different protection channels are fed to the coincidence circuit (logic element I). In one of the protection channels, the false signal is delayed by the coincidence circuit, since the other inputs of the coincidence circuit are not present. The drawing shows a block diagram of the proposed device. (The drawing shows the signal level of all protection channels during normal operation of the converter bridge, event 0-0) In this case, the organs 1 are set to operate with the currents of the winding windings of the transformer 2, which are nominal, therefore their outputs will have a signal from the circuit Sov. Falls 3, triggered only if there are two signals 1 at their outputs, will also have a signal at its output. This signal passes through the OR 4 circuit and is inverted by an inverter 5, from which signal 1 is fed to the input of the coincidence circuit (element) b Blocking channel, soda The element OR 7 and the inverter 8 also emit a signal 1 o. The reacting body 9 is configured so that it operates when the bridge current exceeds the nominal, therefore during normal operation of the bridge it gives a signal. Coincidence circuit 6, in contrast to the coincidence circuit, 3 works only when On all its inputs of signal O. In normal operation of the bridge, one signal O and two signals 1 occur at the input of element 6, so the protection, fixing the normal operation of the bridge, gives a signal. If the player loses, any element except element 6 fails, then false there will be no protection, since only two signals will be fed to the input of element 6. This characterizes the device being described as more reliable than the prototype. During reverse breakdown or isolation of one of the gates of bridge 10, currents of different polarity increase in two damaged phases of the transformer 2 valve winding, which are measured by current sensors 11 "Secondary currents of these sensors create a voltage drop across the load resistors 12 of the respective phases - voltage whose polarity with respect to the middle points of the resistors and the inputs of the reacting organs 1 is such that only one of the reacting organs of each damaged phase with an emergency current is triggered, and the second lock mc Signals from two triggered reacting bodies 1 are fed to the inputs of three of the six coincidence circuits 3, but only one of them comes together about the speed of this coincidence circuit, the signal goes to the WL 4 circuit, then to the inverter 5, and from it the signal O arrives When the breakout or overlap of the isolation of the bridge valve is rectified, the rectifying current of bridge 10 does not increase; therefore, a resolving signal O comes from the reacting organ 9 to the coincidence circuit 6 At the same time, the blocking circuit from the main channel operates cient ILTII 7 and inverter ON, from which the enable signal O is supplied to the coincidence circuit 6. In the presence of signals on all three inputs srabatshaet protection element 6 and outputs a signal at its organo executive

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Claims (1)

DEVICE FOR PROTECTING A DC-CONVERTER ELECTRIC TRANSMISSION BRIDGE, containing a reacting element included in the bridge rectified current sensor circuit, different-polar reacting elements included in the phase current sensor circuits, matching signals of the phase reacting organs and the OR logic circuit connected to their outputs, differing in order to increase reliability, to the output of the OR circuit is connected via an additional inverter a coincidence circuit, the second input of which is through another additional inverter and additional The final OR circuit is connected to the outputs of the phase reacting organs, and the third input is connected to the output of the reacting organ of the rectified current.