JPH0572166B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for inspecting a stationary offset mode type relay.

Conventional technology Offset mode relays are used for distance measurement, direction determination, step-out detection, field loss detection, etc.
It has operating impedance characteristics as shown in the figure.
In the figure, operating region A shows the characteristics of a field loss relay, in which θ ₁ is fixed at -90 degrees, and offset value X ₁ and reach setting value X ₂ are each independently set. Operating area B is the offset value of area A x ₃ and the reach is
The operating _region C shows the distance relay characteristics where θ ₁ is replaced with θ ₂ and the offset value is X ₅ and the reach is X ₆ .

Among relays with such characteristics, those equipped with a check circuit are becoming popular as relays become stationary.
FIG. 3 shows a block diagram of a conventional field loss relay with inspection function. Detection input IN ₁ from the protected object,
One of IN ₂ is the comparison standard and the other is the comparison input,
These inputs IN ₁ and IN ₂ are subjected to waveform processing through filters 1 and 2, respectively. Here, filters 1 and 2
The circuit elements used differ depending on the protection function, such as a band pass filter, a low pass filter, or a phase shifter. The signals that have passed through filters 1 and 2 are added and subtracted from each other in addition and subtraction circuits 3 and 4, and then passed through a shaping circuit that obtains a rectangular wave as a result of the calculation. The outputs of both circuits 3 and 4 are ANDed by an AND circuit 5, and a phase comparator 6 determines the phase difference between this output and the settling phase, and furthermore, a protection output OUT is taken out via a timer. The phase comparator 6 is
When the output of the AND circuit 5 is at a high level for 1/2 time of one cycle (the outputs of circuits 3 and 4 are both on the same phase side), a high level output is obtained; It is configured to obtain a low level output when the output of the AND circuit 5 is on the opposite phase side), and generally the critical operation is when the output of the AND circuit 5 is at a high level for 1/4 hour of one cycle, and the operation is critical during that time. I am trying to make it work when the level is higher than that.

The inspection circuit 7 normally returns the auxiliary relay 7A to apply the inputs IN ₁ and IN ₂ to the filters 1 and 2, respectively, and sends the two-phase oscillation outputs (inspection signals) φ ₁ and φ ₂ to the filters 1 and 2. Please refrain from inputting. Then, during inspection, operate auxiliary relay 7A and input
Instead of IN ₁ and IN ₂ , the oscillation outputs φ ₁ and φ ₂ are connected to filter 1,
2 to check the operation of circuits 1 to 6. For example, if the operating impedance characteristics of circuits 1 to 6 are in region A in FIG. 2, the oscillation outputs φ ₁ , φ ₂
is a signal having a phase and magnitude corresponding to the inside of region A.

Problems to be Solved by the Invention In the conventional inspection method, the inspection circuit 7 needs to be configured to obtain an inspection signal depending on the target relay, and requires a different design for each relay. Furthermore, even if the relays are of the same type, changing the specifications and characteristics requires changing the inspection circuit, which poses problems in terms of design and operation. For example, if the offset set value and reach set value are changed depending on the object to be protected, the magnitude and phase of the outputs φ ₁ and φ ₂ of the inspection circuit 7 will be changed when changing from characteristic A to B in FIG. It takes time and effort.

Furthermore, in the conventional system, input signals and inspection signals are cut off and turned on using mechanical contacts of an auxiliary relay, which poses reliability problems due to the possibility of poor contact of the contacts.

Means and Effects for Solving Problems The present invention is characterized in that the filter and the protection arithmetic circuit after the addition/subtraction circuit are individually inspected. The inspection signal is applied to force the input to the inspection signal, and the inspection signal is applied in common to the protection calculation circuit at a level sufficiently higher than the filter output during inspection through a diode, and the input is forced to the inspection signal. The output of the filter is detected by a level comparison circuit during inspection to check the operation of the filter, and the operation of the protection arithmetic circuit is checked by generation of the protection output.

Embodiment FIG. 1 is a circuit diagram showing an embodiment of the present invention, and the same parts as shown in FIG. 3 are designated by the same symbols. Inspection circuit 11 connects inspection signal φ ₁ to diode 1
Input signals to filters 1 and 2 via 2 and 13
The configuration is such that the check signal φ 1 is applied together with IN ₁ and IN ₂ , and the check signal φ ₁ is applied to the filter 1 side input of the addition/subtraction circuits 3 and 4 via the diode 14 . The output of the filter 1 is input to the adder/subtractor circuits 3 and 4 via the resistor 15, and is also input to the comparison input of the level comparator 16. The output of filter 2 is sent to addition/subtraction circuits 3 and 4.
and is also used as a comparison input of the level comparator 17.

The output of level comparators 16 and 17 is AND circuit 1
8, and the inspection command RD of the inspection circuit 11 is given as the gate input of this AND circuit 18. This inspection command RD is input to the OR circuit 20 together with the output of the AND circuit 18 via the logic inverter 19, and the output of the OR circuit 20 is input to the phase comparator 6.
It is input to the AND circuit 21 together with the output of the AND circuit 21, and the output of the AND circuit 21 is used as the protection output OUT.

Here, the inspection command RD of the inspection circuit 11 is set to a low level during non-inspection to close the gate of the AND circuit 18, and a high level output is obtained to the OR circuit 20 through the inverter 19 to keep the gate of the AND circuit 21 open. A protected output from the phase comparator 6 for the input signals IN ₁ and IN ₂ is obtained. In addition, the inspection signal φ ₁ of the inspection circuit 11 is set to a sufficiently negative potential compared to the input signals IN ₁ and IN ₂ during non-inspection, so that the diodes 12, 13, and 14 are rendered non-conductive so that the input signal and the filter output are not transmitted. The effect has ceased.

At the time of inspection, the command RD is set to a high level to open the gate of the AND circuit 18, and the inspection signal φ ₁ is set to a sufficiently large oscillation output compared to the level of the input signals IN ₁ and IN ₂ to be output to the filters 1 and 2. and forcing the inputs to the addition/subtraction circuits 3 and 4 to match the phase and level of the inspection signal. The resistor 15 prevents the check signal passed through the diode 14 from flowing to the output of the filter 1, and also allows the check signal to be applied to the addition/subtraction circuits 3 and 4 in priority to the output of the filter 1.

Therefore, during inspection, the outputs of filters 1 and 2 become filter outputs for inspection signal φ ₁ and the inputs of addition/subtraction circuits 3 and 4 also become inspection signal φ ₁ and the output of filter 2 (filter output for φ ₁ ).

The outputs of the level comparators 16 and 17 are suppressed by the AND circuit 18 when not inspected, and output at a high level when the output level of the filters 1 and 2 (output level for φ ₁ ) is within a predetermined range during inspection. When the output is lower or higher than that, a so-called window comparator operates to obtain a low level output.

Therefore, during inspection, it is possible to check whether the functions of filters 1 and 2 are normal using level comparators 16 and 17 and AND circuit 18, and addition/subtraction circuits 3 and 4.
The normal operation of the subsequent protection arithmetic circuits up to the phase comparator 6 can be checked as the output of the AND circuit 21 by applying in-phase inputs to the addition/subtraction circuits 3 and 4 using the check signal φ ₁ .

Effects of the Invention According to the present invention, the inspection signal of the inspection circuit is inputted to the filter with priority over the input signal, and inputted to the protection calculation circuit with priority over the output of the filter, and the filter and the protection calculation circuit are checked individually. Therefore, the inspection signal for one phase is sufficient, and the same inspection signal is sufficient even when the offset or reach of the operating characteristics is changed or for different relays. In addition, switching by mechanical contacts is not required to apply a check signal, resulting in a highly reliable relay with a check function.

[Brief explanation of drawings]

Figure 1 is a circuit diagram showing one embodiment of the present invention, Figure 2 is a circuit diagram showing an embodiment of the present invention.
The figure is a complex diagram showing an example of the characteristics of an offset mode relay, and FIG. 3 is a circuit diagram of a conventional relay with an inspection function. 1, 2...filter, 3, 4...addition/subtraction circuit,
6... Phase comparator, 7, 11... Inspection circuit, 1
6,17...Level comparator.

Claims (1)

[Scope of Claims] 1. A static offset motor type equipped with a plurality of filters that directly input a plurality of input signals and process their waveforms, and a protection calculation circuit that directly inputs the outputs of the filters and performs protection calculations on each of them. In the relay, a first diode circuit that directs an inspection signal at a level sufficiently higher than the input signal at the time of inspection as a direct input to each of the filters; a second diode circuit that directs the inspection signal as a direct input to each of the protection arithmetic circuits; a level comparison circuit that checks the operation of each filter from the output level of each filter during inspection; and an output of the protection arithmetic circuit during inspection. A relay inspection device comprising: a gate circuit that checks the operation of the protection arithmetic circuit;