SU1365223A1 - Relay protection arrangement - Google Patents

Abstract

The invention relates to the field of electrical engineering, namely, to relay protection, and is intended for directional protection of high-voltage power lines. The purpose of the invention is to increase reliability by increasing the number of elements covered by the test test. This is achieved by switching to the inputs of the formation blocks of 3 and 4 currents and voltages in the first position they switch. 8 of the same polarity, amplitude and shape at their output, the signals will have the character of periodic damped oscillations. The resulting periodic damped oscillations are used to check the remaining elements of the device. 2 Il. and in (L

Description

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The invention relates to the field of electrical engineering, namely, to relay protection, and is intended for directional protection of high-voltage power lines.

The purpose of the invention is to increase reliability by increasing the number of checked elements of the device covered by the test check.

Figure 1 shows the structural diagram of the device; figure 2 - the timing diagram of his work.

The device for relay protection contains sensors 1 and 2 of symmetrical components of current and voltage connected to blocks 3 and 4 of the formation of voltages proportional to current and voltage with identical frequency-selective properties. The outputs of blocks 3 and 4 are connected to block 5 of the comparison of electrical quantities. Keys 6.1 and 6.2 through two-terminal 7.1 and 7.2 are connected respectively to the other inputs of blocks 3 and 4. Key 6.1 is connected to switch 8, which connects the two-pole to positive with a negative power bus.

The device works as follows.

When the device is in operating mode, the keys 6.1 and 6.2 are in the open state, and the two-port networks 7.1 and 7.2 do not affect its operation. The input signals from sensors 1 and 2 of the symmetrical components of the current and voltage are fed to the inputs of blocks 3 and 4 of the formation of voltages proportional to current and voltage, and after appropriate transformations are received to the block 5 comparison of electrical quantities. In the absence of damage to the line, the values of the signals at the outputs of the formative blocks do not correspond to the condition of the operation of the comparator unit. In the event of damage in the zone of the device, the values of the signals at the output of the formation blocks change, which leads to the operation of the comparison block.

When the device is switched to the test mode, the Keys 6.1 and 6.2 are closed, the inputs of the voltage shaping blocks proportional to the current and voltage are given signals caused by the two-pole current.

When used as a two-pole capacitor, the signal at the input

de blocks 3 and 4 of the formation (with their active input resistance) has the form of an exponent (Fig.2).

When applying to the inputs of the blocks 3 and 4 of the formation, containing, for example, filters, the second order of signals U and and (Fig. 2a) in the first position of the switch 8 of the same polarity, amplitude and shape, the response of identical filters of these blocks will be the same and the signals (and and) at their output will have the character of periodic damped oscillations of the same

shape and amplitude (figa :). Moreover, by selecting the time constant of the exponential signal, it is possible to obtain an oscillation waveform that is close to sinusoidal without a pronounced aperiodic component. The resulting periodic damping; oscillations are used to test the remaining elements of the device: both the units of formation of quantities and the unit of comparison.

In the absence of a malfunction in the device, the reaction of blocks 3 and 4 and block 5 of the comparison (and ..) to the test actions that have occurred is unambiguous.

In another position, the switch 8 when the keys 6.1 and 6.2 are closed on

the input of blocks 3 and 4 is fed to the signals and and and (figb) opposite in g

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of the same amplitude and form of the output signals

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blocks and Uj correspond to the condition of failure of the comparison circuit. In this case, the directivity and settings of the relay are checked, since the failure of any filter element leads to a change in the current amplitude of the signal at the output of block 3 and the frequency of free oscillations of the transient process in the filter.

If units 3 or 4 malfunction in the current circuit or the voltage at their output, there will be damped oscillations that are not consistent with each other, since the parameters of the faulty unit will differ from those of a serviceable unit. This will lead to failure of the relay in the test mode, when the polarity of the signals at the input of the formation blocks will correspond to the operation of the relay in the zone of action, or it may lead to a false trigger of the relay, when the polarity of these signals will correspond to the operation of the relay out of range.

Thus, in the proposed device, it is possible to test the operation of a relay with two characteristic values.

Claims (1)

Invention Formula A relay protection device containing voltage-forming units proportional to current and voltage with identical frequency-selective systems, the first inputs of which are connected respectively to the sensors of the symmetrical components of the current and voltage connected to the protected line, the second inputs v: / - x: / but The coils are connected respectively to the beginnings of the first and second circuits, consisting of a series-connected switching element and a two-port circuit, and the outputs of the blocks are connected to the inputs of the electrical quantity comparison unit, characterized in that, in order to increase reliability by increasing the number of elements covered by the test, the end of the first circuit is connected via an additionally inserted switch to the power supply buses of different polarities, and the end of the second circuit is connected to the power supply buses of one of the polarities. / l -t}