SU612338A1 - Arrangement for protecting synchronous generators from earthing (fault to frame) in a single point of exciting circuit - Google Patents

Description

ngilnyh systems of life and where anachigepyny-. higher frequencies in the rectified voltage of horn breakdown, such protection has a limited area 5

application and lack of sensation.

The aim of the research is to increase the sense of sensation.

 The ego is reached by heme, which is a device for protecting synchronous generators from earth faults (housing); at one point of the excitation circuit, which contains a measuring bridge, in which the first sensor is formed in series with the excitation winding and the separation capacitor, / the second arm - compensating the condensate. rum, and the third and fourth shoulders are formed by resistors, an auxiliary source is included in one of the bridge diagonals,

Nor, but to another executive body, additionally contains a reactive BSD and a resistor to compensate for isolator resistance. excitation circuit, the reactive unit is connected in series with the separation capacitor, forming with it a resonant circuit at the frequency of the auxiliary voltage source, and the resistor compensation compensation of the isolation of the excitation circuit is connected in parallel to the compensating condensation circuit. The schematic diagram of the device is shown. It contains a winding 1), capacitance 2 on the ground of the excitation circuit, resistance 3 of the isolation of the excitation circuit, separation capacitor 4 $ capacitor 5, used to compensate for line capacitance of the bridge circuit for operation, resistors 6 and 7 with the same resistance values, protection protection actuator 8, auxiliary voltage source 9, reactive unit U, form a resonant circuit at the frequency of the auxiliary power source with the coupling capacitor , and a resistor 11, which serves to compensate for the effect of the insulation resistance of the excitation circuit on the operation of the bridge circuit, this protection uses the principle of imposing on the excitation winding of an alternating voltage from the auxiliary source. However, the source voltage frequency is assumed in the range (0.2-0.7) of the rated mains frequency. Voltages with frequencies in the specified range cannot appear in the excitation winding ppHpnamnnm g-nnr-jniraiJTiix H gigtechch hli pgch-3-

gantry source. Resistors may be included to adjust the circuit to the shoulders of the bridge in series with the reactive unit and the compensation capacitor.

The reactive elements have approximately zero resistance for the auxiliary source current and significant resistance for the currents of other frequencies, thereby limiting the value of interference voltages at the input of the actuator after applying protection to the excitation circuit. In this case, the current in the circuit; generator 9, resistor 6, unit Yu, capacitor 4 and capacitor in parallel to the ground circuit

depends on the values of the last two values.

Using compensation elements - capacitor 5 and resistor 11 in the compensation circuit: generator 9, resistor 7 and capacitor 5 connected in parallel, and compensation resistor 11 set the same vector current as in the first circuit.

Claims (3)

As a result of this stress vector, the bumps are inherently real time, even during re-transition processes. . Pre-reactive unit Yu with & locally with split capacitor 4 is burned out in resonance at frequency of support 2 and isolation resistance 3 of resistors 6 and 7 are equal in amplitude And coincide in phase, and the signal at the input of the actuator 8 is zero. With decreasing insulation resistance values, the value of the current vector in the circuit with the reactive unit changes. 10, while the value of the current in the other circuit (with significant resistance in the diagonal of the bridge circuit) remains constant. As a result, the voltage at the input of the executive body is proportional to the difference of the current vectors of the two specified circuits. One of these vectors characterizes the state of isolation of the excitation circuit at the moment of setting and turning on the protection, and the other - the final state of isolation. Detuning the actuator of the unbalance voltage protection, which, when used with a bandpass filter at its input, may approach zero, allows for highly sensitive protection that can be used on generators with any excitation system. Claims of the Invention To protect synchronous generators from short circuits: 1 (and to ground (case) a measured mosg, in which the first shoulder is formed by successively connected excitation winding and a separating capacitor, the second shoulder is formed by a compensating capacitor, and the third and fourth shoulders are formed by resistors, One of the bridge diagonals includes an auxiliary voltage source, and the other has an executive body, characterized in that, in order to increase the sensitivity, it also contains reactive the block and the resistor are compensated for isolation of the circuit, the reactive unit is connected in series with the separation capacitor to form a resonant circuit with it at the frequency of the auxiliary voltage source, and the resistor for the compensation of the insulation resistance of the exciter circuit is connected in parallel to the compensating capacitor. attention in the examination: 1.Gostev, I.V., Sagatepova, E.A., Setting up protection against a ground fault at one point in the center of excitation of the gene -. Rator, Electric Power Stations, 1959, No. 8, p. 51-53. 2. Guidelines for Relay Calls, vol. 5, Zaschlta blocks generator-trisnfo) mator and generator-autotransformer, Energie, 1963, p. 39 3.Tuganov D.V. Sensitively wired excitation circuits of generators and synchronous compensators from the ground fault at one point. Operating experience of relay protection, automation and telemech shki in the system Dneproznergo, VTI ORGRES, 1964. p. 92-96.