JPH0519373B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an over/under voltage relay, and particularly to an over/under voltage relay suitable for improving the protection function when a disconnector installed in an electric circuit is turned on at an abnormal voltage. Regarding relays.

[Background of the invention]

Conventional overvoltage relays or undervoltage relays include an overvoltage detection circuit having an output relay X1 and an undervoltage detection circuit having an output relay In the case of overvoltage, the output relay X1 is energized via the waveform continuation circuit TDD1, and in the case of undervoltage, the output relay It was composed of Therefore, if there is already an abnormal voltage (overvoltage or undervoltage) when the disconnector is turned on, there is a time delay due to the waveform continuity circuit TDD1 or time measurement circuit TDE1, and during this time delay, the output relay X1 or the detection circuit is There was a problem in that the output relay X2 did not operate and temporarily issued a signal indicating that the line voltage was normal.

[Purpose of the invention]

It is an object of the present invention to provide a system that can prevent malfunctions at startup even when a disconnector is turned on at an abnormal voltage with respect to the normal state voltage of the secondary circuit, has excellent reliability, and has an excellent protection function for the circuit. Our purpose is to provide voltage relays.

[Summary of the invention]

The present invention provides an over/under voltage relay that includes an input terminal connected to a secondary circuit of a disconnector, a full-wave rectifier circuit for rectifying and smoothing the output of this input terminal, and a stable circuit connected to the full-wave rectifier circuit. a power supply voltage supply means having a stabilized power supply circuit and a capacitor connected to the output of the stabilized power supply circuit; and a comparator that compares the voltage of the capacitor with a reference voltage and generates an output when the voltage reaches the reference voltage. A control power supply establishment detection circuit, a voltage detection means connected to an input terminal in parallel with the power supply means, and an overvoltage detection circuit and an undervoltage detection circuit connected to the output terminal of the voltage detection means, An abnormal voltage detection means that detects at least one of overvoltage or undervoltage with respect to the voltage in a normal state and generates an output, and the logic of the output of the overvoltage detection circuit and the output of the power supply means connected to the abnormal voltage detection means. The first to balance
A second OR gate that takes the logical sum of the outputs of the OR gate, the undervoltage detection circuit, and the output of the power supply means, and the logic of the outputs of the first OR gate, the second OR gate, and the output of the control power supply establishment detection circuit. Take the product 3
It has an input AND gate, and the output of this 3-input AND gate is fed back to the input of the first OR gate and the second OR gate connected to the power supply means, and output is prohibited before the power supply is established. When the power is established, the first OR gate and the second
It is connected to a holding means for holding the logical product of the output of the OR gate and an abnormal voltage detection means, and performs a count proportional to the intermittent time of the abnormal voltage with respect to the voltage in the normal state of the secondary circuit, and this count value reaches a predetermined number. A counting means that generates an output when the target is reached, and two inputs that take the output of this counting means and the output of the holding means as inputs.
It has an AND gate, and when both the output of the holding means for abnormal voltage and the output when the count value of the coefficient means reaches a predetermined number are input, the voltage of the input terminal becomes the voltage of the normal state of the secondary circuit. an output means that generates an output indicating that there is an abnormality, and a circuit breaker connected to the output means and connected to the secondary circuit, which can be closed when the voltage of the secondary circuit is in a normal state. The present invention is characterized in that it includes an opening/closing means for controlling the opening/closing operation of the filter, and the power supply means is configured to supply power to the abnormal voltage detection means, the counting means, the output means, and the related means.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 10. The first embodiment of the present invention is shown in FIGS. 1 to 5.
This will be explained using figures. FIG. 1 is a block diagram showing the overall configuration of a first embodiment of the present invention.

Next, the operation of this embodiment from when the disconnector is turned on until the power is turned on and the control circuit operates will be explained with reference to FIGS. 2 to 4.

The voltage applied to the input terminal 10 is full-wave rectified by a rectifier 12 via a transformer 11 and smoothed by a capacitor 13 . Furthermore, the smoothed voltage is the reference voltage of the Zener diode 14, and the stabilized power supply circuit 1
The voltage is stabilized by 5, stored in a capacitor 16, and applied to a control circuit 17. Next, the configuration of the control power supply establishment detection circuit 18 is such that the stabilized power supply is connected to the resistor 19,
20 and is inputted to an inverting input terminal of a comparator 21, while a reference voltage from a resistor 22 and a Zener diode 23 is inputted to the non-inverting input.

Now, if an input voltage as shown in FIG. 3a is applied to the input terminal 10, the potential F of the capacitor 16 mentioned above gradually increases as shown in FIG. 3b. As a result, the potentials G and H of the non-inverting and inverting inputs of the comparator 21 change as shown by G and H in FIG. 3b, respectively. By selecting the ratio of the Zener diode 23 and the resistors 19 and 20 so that both have the relationship shown in the figure, the output A of the comparator 21 is as shown in Figure 3c when the power supply voltage F reaches almost the final voltage. The signal changes from the "H" level to the "L" level.

The control circuit 17 includes an overvoltage detection circuit 24 and an undervoltage detection circuit 25, each of which outputs a signal when an abnormal voltage is detected.

Now, in the so-called normal state where the input voltage is below the overvoltage setting value and above the undervoltage setting value, the comparator 21
Since the output A of is inverted to "L" level, the input to AND gate 27 via NOT gate 26 becomes "H" level. In addition, the outputs B and C of the overvoltage and undervoltage detection circuits 24 and 25 are both "L".
AND gate 27 via NOT gates 28, 29 and OR gates 30, 31, respectively.
The input to is at "H" level. This results in
The output of AND gate 27 becomes "H" level,
The other input of OR gates 30 and 31 is also "H"
level, and the output of AND gate 27 becomes “H”
It will be held at the level.

Further, the control circuit 17 includes a limiting circuit 32, which outputs a signal after a time limit setting value has elapsed when an overvoltage or an undervoltage occurs from the above-mentioned normal state. When the circuit is in a normal state when the disconnector 3 is turned on, the output D of the time limit circuit is at the "L" level.
The input to the AND gate 34 via the NOT gate 33 becomes "H" level. Also, since the output of the AND gate 27 is held at the "H" level, the input of the AND gate 34 is at the "H" level, and the output E is at the "H" level, turning the transistor 35 ON.
As a result, the output relay 36 as a switching means is energized, and at this time, the circuit breaker installed in the electric circuit can be closed.

Next, when the above-mentioned normal state shifts to undervoltage, the output from the undervoltage detection circuit 25 becomes "H" level, but the output of the AND gate 27 is held at "H" level, so it does not change. . However, the time limit circuit 32 works and outputs after a certain period of time.
The output E of the AND gate 34 is changed from the "H" level to the "L" level, the output relay 36 is deenergized, and an abnormal voltage detection state is established. The same applies when an overvoltage occurs in a normal state. In addition, in the event of a power outage from a normal state, the power supply is capacitor 1.
Compensate with 6. These time charts are shown in Figure 4a.

Next, if there is an abnormal voltage in the electrical circuit before the disconnector 3 is turned on, for example in the case of overvoltage, the comparator 21
The input to the AND gate 27 of the undervoltage detection circuit 25 is at "H" level, but the input to the AND gate 27 of the undervoltage detection circuit 25 is at "H" level.
The output B from 4 becomes the "H" level, and the output of the AND gate 27, which was at the "L" level when the power was established, cannot become the "H" level, that is, the output relay 36 is not energized and the circuit breaker is closed. cannot be input. In addition, in the case of a power outage, the circuit does not work from the beginning, so the output relay 36 is not energized, and the circuit operates in the same manner as in the case of overvoltage before the circuit breaker is turned on for an undervoltage that is sufficient to establish a power supply. conduct. A time chart in the case of overvoltage from the time when the disconnector 3 is turned on is shown in FIG. 4b. In addition, Fig. 4 a,
In b, A is the output of the control power supply establishment circuit 18, B is the output of the overvoltage detection circuit 24, C is the output of the undervoltage detection circuit 25, D is the output of the time limit circuit 32, and E is the output of the AND gate 34 of the output circuit. show.

In this embodiment, since the control circuit power source and the detection voltage are obtained from the same terminal, the output relay is in an operating state in which the relay has detected an abnormal voltage until the disconnector 3 is turned on.

Even after the disconnector 3 is closed, the output relay maintains the operating state of the relay and prevents the circuit breaker 1 from closing even after the disconnector 3 is closed.

When the disconnector 3 is turned on, if the voltage is normal, the circuit operation at the initial abnormal voltage is canceled.

As mentioned above, the output relay 36 as a switching means provided in the output means is energized when both the overvoltage detection means 24 and the undervoltage detection means 25 are in an inoperable state, and this output means outputs an output when the voltage is normal. Therefore, it is possible to prevent a large current from flowing into the power supply circuit 60 in the event of malfunction during undervoltage or overvoltage.

Note that lowering the voltage level that detects the establishment of control power supply to around the lower limit of the guaranteed power supply voltage for ICs used for comparators, over/undervoltage detectors, and counters for time-limiting circuits will speed up the time until power supply is established. can do. In this case, each gate circuit may be configured with a blocker (for example, a diode, a transformer, etc.) that functions below the IC's guaranteed power supply voltage.

According to this embodiment, since the detection voltage and the power supply for the control circuit are obtained from the same line, there is no need for wiring compared to the case where the power supply for the control circuit is provided separately, and the relay can be made smaller. can.
In addition, in an undervoltage state, the output relay 36 is not energized even if the disconnector is turned on, so malfunction can be prevented, and in an overvoltage state, even if the disconnector is turned on, no current flows through the coil of the output relay 36, so the power supply is turned on. The load on the supply means is reduced, heat generation is reduced, and reliability can be improved. FIGS. 5A and 5B are divided circuit diagrams of the overall configuration of the over/under voltage relay in this embodiment.

Next, the operation of each part in FIGS. 5A and 5B will be explained.

In the input and rectifier circuit that is the voltage detection means 50, the input voltage is stepped down by a transformer 101 and full-wave rectified by a diode bridge 102. In the overvoltage detection means 52 and the undervoltage detection means 54,
The operation of the overvoltage setting circuit and undervoltage setting circuit is as follows.

The switches 103 and 104 control the resistance 105,
The resistance ratio of 106 is changed to set overvoltage and undervoltage respectively. In addition, Zena diode 140,
107 is for over-input protection, and a diode 108 is for supplying a charging current from the signal system (transformer 101) to the power supply smoothing capacitor 109 when the input is turned on, thereby speeding up the power supply establishment time.

The overvoltage level detection circuit will be explained.

The potential of the peak hold capacitor 110 is further smoothed by a resistor 111 and a capacitor 112, and is input to the inverting inputs of comparators 113 and 114, and the reference voltages (ratio inverting inputs of each comparator) are compared. When overvoltage is input, the inverted input potential of comparators 113 and 114 increases. Comparator output "L" → comparator 115 output "L", comparator 116 "H" → comparator 115 output "L", counter 117 reset terminal "L"
(Reset release), transistor 118 base “L”
(Transistor 119 is normally "L") Self-excited oscillation starts (Transistors 118 and 119 are for stopping self-excited oscillation). The reference voltage is set so that the output of the comparator 113 is inverted when the overvoltage exceeds 100%, and the output of the comparator 114 is inverted when the overvoltage exceeds 13%.

In the counting means 56, the oscillation circuit is connected to the comparator 12.
0 and a comparator 121 used as an amplifier. The counter circuit is a counter IC
117, and supplies its output to an overvoltage/undervoltage operation time setting circuit.

The excess/deficiency discrimination circuit of the output means takes the logical sum of the overvoltage signal of 130% or more and the maximum bit output of the counter, and supplies the signal to the input of the AND circuit 126 or 127.

On the other hand, the comparators 115 and 130 "L" output the transistors 128 and 129 collectors "H" → AND
126, 127 “H” → Transistor 131 collector “L” → Transistor 132 collector “H” →
The output relay coil is de-energized. Note that the relay coil is in an excited state under normal conditions.

In the above configuration, the operation when input is input is as follows.

Before power supply voltage (Vcc) is established = by comparator 141
Connect one end of AND126, 127 input to diode 13
3 to "L". (Preventing relay operation before Vcc is established). Also, the analog switches 134 and 135 are made non-conductive (to prevent over/under operation indicator LED from lighting up).

After establishing the power supply voltage (Vcc) (1) Normal case = comparator 115, 130 outputs are both "H" → diode 1
36a anode potential "L", transistor 131
Base potential "L" → Transistor 132 conduction relay excitation (2) In case of abnormality (overvoltage or undervoltage) = Either comparator 115, 130 output is "L" → Diode 136a anode "H" → Transistor 138 collector "L" ”→The relay coil is not energized,
This prevents malfunction.

Next, a second embodiment of the present invention will be described with reference to FIGS. 6 to 8.

In this embodiment, power is established quickly by passing electricity from the signal detection element to the power supply element when human power is turned on.

Return to Figure 6, turn on input 201 → transformer 20
2, diode bridge 204, capacitor 20
5, the power is stored in the smoothing capacitor 207 via the rectification and smoothing → stabilization circuit 206. The time course of power supply establishment at this time is shown in FIG. 7A. (The above power supply circuit 2
21) On the other hand, the detection circuit 222 is rectified by a transformer 203 and a diode bridge 208 → a resistor 209,
The voltage is divided by a variable resistor 210 and sent to a detection circuit 211.
At this time, the rise of the detection circuit input voltage is instantaneous (strictly speaking, there is a delay due to intervening elements such as a transformer), and when the input 201 is turned on, the detection circuit input voltage is higher than the power supply voltage. Therefore, current flows through the diode 212 to the smoothing capacitor 207, and the power supply is quickly established as shown in FIG. 7B. The above is a connection when the detection circuit input voltage does not exceed the power supply voltage during steady state (maximum setting value in the case of overvoltage relays, etc.). In the above case, it can be handled by connecting the broken line in FIG. 6 (as the detection circuit input voltage increases, the potential of the capacitor 205 also increases.
The cathode potential of is greater than the anode potential. ) FIG. 8 shows a modification of this embodiment. When the power supply voltage is larger than the input signal rectification value during normal operation, the diode anode is connected as shown in the figure to further speed up the establishment time (FIG. 7C). Note that the connections indicated by broken lines in FIG. 8 are the same as those in FIG. 6 and will therefore be omitted.

Next, a third embodiment of the present invention will be described with reference to FIGS. 9 and 10.

The purpose of this embodiment is to provide a compact and highly reliable relay by sharing delay circuits of conflicting elements, reducing the number of circuit components.

Examples of relays that include mutually contradictory elements include overvoltage and undervoltage relays that include an overvoltage detection element (hereinafter referred to as OV element) and an undervoltage detection element (hereinafter referred to as UV element). Each element generally has the configuration shown in FIG. That is, the level detection section 301
The input amount and the reference amount are compared by the delay circuit 302.
After being delayed by a preset time, the output circuit 303 obtains an external output. By the way, since these contradictory elements do not operate and output at the same time, it is not necessary to have each of the delay circuits 2 independently, but they can be shared to simplify the circuit.

This embodiment will be explained below with reference to FIG.

During normal operation, the output of both the overvoltage detection circuit 1A and the undervoltage detection circuit 301B is "L", so the output of the OR gate 304 is "L", and therefore the output of the counter 302A is "L".
is in a reset state, so the output of the counter 302A is "L", and the output circuits 303A and 303B are inoperative.

301A (301B) when overvoltage (undervoltage)
Output "H" → OR gate 304 output "H" → Counter 302A reset release counter 302A count start → Counter output "H" → AND gate 3 via operating time setting switches 302B and 302C
Input to 06,305 → AND gate 306,30
5 output "H" → output circuits 303A and 303B operate.

According to this embodiment, delay circuits of contradictory elements can be shared.

According to the above embodiment, the detection voltage and the power supply for the control circuit inside the relay are obtained from the same line, and the combination of the gate circuit keeps the output relay in a non-excited state in the event of an initial abnormal voltage, so the circuit breaker This makes it possible to protect the electrical circuit with high reliability.

[Effects of the Invention] According to the present invention, even if the disconnector is turned on when the voltage is higher than the voltage in the normal state of the secondary circuit, malfunction can be prevented, resulting in excellent reliability and an excellent protection function for the circuit. Over/under voltage relays can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the overall configuration of one embodiment of the present invention, FIG. 2 is a circuit diagram of one embodiment of the present invention,
FIGS. 3 and 4 are waveform diagrams of various parts of an embodiment of the present invention, FIGS. 5A and 5B are specific circuit diagrams of an embodiment of the present invention, and FIGS. 6 and 8 are A circuit diagram showing a circuit for speeding up the establishment of power supply, Figure 7 is similar to Figure 6 and Figure 8.
9 is a block diagram showing the general configuration of a relay equipped with delay circuits of contradictory elements. FIG. 10 is a circuit diagram of a relay that shares delay circuits of contradictory elements. The figure is a block diagram showing an example of high voltage power receiving equipment. 50: voltage detection means, 52: overvoltage detection means,
54: Undervoltage detection means, 56: Counting means, 5
8: Output means, 60: Power supply means.

Claims (1)

[Claims] 1. An input terminal connected to the secondary circuit of the disconnector, a full-wave rectifier circuit that rectifies and smoothes the output of this input terminal, a stabilized power supply circuit connected to this full-wave rectifier circuit, and this stabilized power supply circuit. power supply voltage supply means having a capacitor connected to the output of the control power supply establishment detection circuit having a comparator that compares the voltage of the capacitor with a reference voltage and generates an output when the reference voltage is reached; voltage detection means connected to the input terminal in parallel with the power supply means;
It is connected to the output terminal of the voltage detection means and has an overvoltage detection circuit and an undervoltage detection circuit, and detects at least one of overvoltage or undervoltage with respect to the voltage in the normal state of the secondary side electric circuit and generates an output. Abnormal voltage detection means, a first OR gate connected to the abnormal voltage detection means and ORing the output of the overvoltage detection circuit and the output of the power supply means, the output of the undervoltage detection circuit, and the power supply means. It has a second OR gate that takes the logical sum of the outputs of the circuit, and a three-input AND gate that takes the logical product of the outputs of the first and second OR gates and the output of the control power supply establishment detection circuit. The output of the 3-input AND gate is fed back to the input of the first OR gate and the second OR gate connected to the power supply means, and the output is prohibited before the power supply is established, and when the power supply is established, the above holding means for holding the logical product of the output of the first OR gate and the output of the second OR gate; and a holding means connected to the abnormal voltage detection means, the intermittent period of the abnormal voltage with respect to the normal state voltage of the secondary circuit. Perform counting proportional to
It has a counting means that generates an output when the counted value reaches a predetermined value, and a two-input AND gate that receives the output of this counting means and the output of the holding means as input, and outputs an output in response to the abnormal voltage of the holding means. An output indicating that the voltage at the input terminal is abnormal with respect to the voltage in the normal state of the secondary circuit when at least one of the outputs is input when the count value of the counting means reaches a predetermined number. an output means for generating
The circuit breaker connected to the output means and connected to the secondary circuit is provided with switching means for controlling the opening/closing operation of the circuit breaker so that it can be turned on when the voltage of the circuit is in a normal state, and the power supply means is connected to the secondary circuit. An over/under voltage relay configured to supply power to abnormal voltage detection means, counting means, output means, and switching means.