JP2010233355A - Protective control apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a protective control apparatus which can suppress heat generation in the components of a logic input circuit to cope with a wide range of logic signals different in a rated voltage. <P>SOLUTION: An analog conversion circuit 12 converts a current and voltage input from a power system through an input transformer 11 into an analog signal, and an A/D converting circuit 13 converts the converted analog signal into a predetermined digital signal. A logic input circuit 15 takes in an external voltage logic signal having a predetermined operation condition and an output condition, and a calculation processing circuit 14 performs a predetermined protective control calculation based on the digital signal in the A/D conversion circuit and the logic signal in the logic input circuit. A logic input control circuit 18 intermittently operates the logic input circuit at the timing for taking in the voltage logic signal from the outside in accordance with the command of the calculation processing circuit 14, while a power supply circuit 19 supplies a control power supply voltage to each circuit so that the control voltage becomes equal to the voltage of the external logic signal of the logic input circuit 15. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a protection control device that detects a system fault and performs predetermined control according to current, voltage, phase, and logic signal input conditions of a power system.

  In general, a protection control device detects a system fault and performs predetermined control based on the current, voltage, phase, and logic signal input of the power system, and inputs the voltage and current of the power system via an input converter. The signal on the secondary side of the input transformer is converted to a predetermined level analog signal by a predetermined analog conversion circuit, and further converted to a digital signal by an A / D conversion circuit, and a predetermined protection control calculation is performed by an arithmetic processing circuit. It detects system faults. In outputting the protection control calculation result to the outside, it is possible to set and control predetermined operation conditions and output conditions by a voltage logic signal from the outside.

  In a conventional protection control device, a logic signal of voltage is continuously input from the outside, and a logic signal is captured by flowing a current into the protection control device. For this reason, there is a large amount of heat generated by the components of the logic input circuit, and there are restrictions such as measures for heat dissipation and limiting the number of logic input circuits if necessary.

  Even when operating a single contactless relay for a plurality of input voltages, even when the input voltage is large, there is one that can reduce the input current to the contactless relay (for example, Patent Documents). 1).

JP 2005-101781 A

  In the thing of patent document 1, the constant current circuit and the bypass circuit are provided. The constant current circuit can handle logic signals of multiple rated voltages, making it possible to suppress the amount of heat generated inside the housing, such as mounting a heat sink for heat dissipation or providing a heat dissipation slit in the case. There is no need to take heat dissipation measures. Moreover, even if an oxide film is generated at the contact portion of the external contact by passing a large current for a certain time by the bypass circuit, the oxide film can be removed and the contact failure of the external contact can be prevented. .

  However, in Patent Document 1, a logic signal of an external voltage is always input continuously, which is not necessarily sufficient as a countermeasure against heat generation.

  An object of the present invention is to provide a protection control device that is further reduced in size by further reducing the amount of heat generation.

  The protection control device of the present invention is a protection control device that detects a system fault and performs predetermined control according to the current, voltage, phase, and logic signal input conditions of the power system, and inputs the current and voltage from the power system via an input transformer. An analog conversion circuit for converting the secondary signal of the input transformer into a predetermined level analog signal, an A / D conversion circuit for converting the analog signal of the analog conversion circuit into a predetermined digital signal, and a predetermined A logic input circuit that takes in a voltage logic signal from the outside in which the operation conditions and output conditions are set, and a predetermined protection control calculation based on the digital signal of the A / D conversion circuit and the logic signal of the logic input circuit An arithmetic processing circuit for outputting the protection control calculation result to the outside via a relay output circuit; A logic input control circuit for intermittently operating the logic input circuit in accordance with the timing of fetching the logic signal, and a control voltage having the same value as the voltage of the logic signal from the outside of the logic input circuit. And a power supply circuit that supplies a power supply voltage for control to the input transformer, the analog conversion circuit, the A / D conversion circuit, and the arithmetic processing circuit.

  According to the present invention, component heat generation of the logic input circuit can be suppressed, a wide range of logic signals having different rated voltages can be dealt with, and contact failure of the external contact that controls the voltage of the logic signal can be prevented.

The block diagram of the protection control apparatus concerning the 1st Embodiment of this invention of this invention. The circuit diagram of an example of the logic input control circuit and logic input circuit in the 1st Embodiment of this invention of this invention. Explanatory drawing of the heat_generation | fever of the logic input circuit in the 1st Embodiment of this invention. Explanatory drawing of the electric current which flows into the logic input circuit in the 1st Embodiment of this invention. The circuit diagram of another example of the logic input control circuit and logic input circuit in the 1st Embodiment of this invention. The circuit diagram of an example of the logic input control circuit and logic input circuit in the 2nd Embodiment of this invention. Explanatory drawing of the heat_generation | fever in the example of the logic input circuit in the 2nd Embodiment of this invention. Explanatory drawing of the heat_generation | fever in the case of another example of the logic input circuit in the 2nd Embodiment of this invention. The block diagram of the protection control apparatus concerning the 3rd Embodiment of this invention. The circuit diagram of an example of the logic input control circuit and logic input circuit in the 3rd Embodiment of this invention. The circuit diagram of an example of the logic input control circuit and logic input circuit in the 4th Embodiment of this invention.

(First embodiment)
FIG. 1 is a configuration diagram of a protection control apparatus according to the first embodiment of the present invention. The current and voltage of the power system are insulated by the input transformer 11, and the current and voltage of the power system are input via the input transformer 11. A signal on the secondary side of the input transformer 1 is input to the input analog circuit 12 and converted into an analog signal of a predetermined level in the input analog circuit 12. An analog signal of a predetermined level obtained by the input analog circuit 12 is converted into a predetermined digital signal by the A / D conversion circuit 13 and input to the arithmetic processing circuit 14. The arithmetic processing circuit 14 also receives a logic signal from the logic input circuit 15. The logic signal is a signal in which predetermined operation conditions and output conditions are set, and is taken into the logic input circuit 15 as a voltage signal from the outside, and the fetched logic signal is inputted into the arithmetic processing circuit 14.

  The arithmetic processing circuit 14 performs a predetermined protection control calculation based on the input digital signal of the A / D conversion circuit 13 and the logic signal of the logic input circuit 15, and protects outside by the output contact 17 via the relay output circuit 16. Outputs control calculation results. That is, the output contact 17 opens and closes in response to the result of the relay output circuit 16 and transmits information on the protection control calculation result to the outside of the protection control device.

  The logic input control circuit 18 controls the logic input circuit 15 according to a command from the arithmetic processing circuit 14 and operates the logic input circuit 15 intermittently in accordance with the timing of taking in a voltage logic signal from the outside. Thereby, even if the logic input circuit 15 is operated intermittently, a logic signal can be captured.

  The power supply circuit 19 uses the control voltage stabilized as the power supply voltage inside the protection control device from the power supply input to each circuit, that is, the input transformer 11, the analog conversion circuit 12, the A / D conversion circuit 13, and the arithmetic processing circuit 14. The relay output circuit 16 and the logic input control circuit 18 are supplied. At that time, the power supply circuit 19 supplies a control power supply voltage to each circuit so that the control voltage has the same value as the voltage of the logic signal from the outside of the logic input circuit 15.

  FIG. 2 is a circuit diagram of an example of the logic input control circuit 18 and the logic input circuit 15 shown in FIG. When an external contact (not shown) outside the protection control device is closed, a voltage logic signal is applied to the logic input circuit 15 of the protection control device. The external contact controls a logic signal input to the logic input circuit 15. For example, when the external contact is closed, a predetermined voltage is generated as a logic signal, and when the external contact is opened, the voltage is zero. And no logic signal is input.

  When a logic signal voltage is applied to the logic input circuit 15 of the protection control device, a current I determined by the resistor 20 of the logic input circuit 15 flows to the photocoupler 21, and a logic signal is input to the arithmetic processing circuit 14 via the photocoupler 21. Is done. At this time, the arithmetic processing circuit 14 outputs a command for intermittently operating the logic input circuit 15 to the logic input control circuit 18. That is, the arithmetic processing circuit 14 outputs a control signal for intermittently operating the photo MOS relay 22 of the logic input control circuit 18. Thereby, the photo MOS relay 22 of the logic input control circuit 18 operates intermittently, the logic input circuit 15 repeats ON / OFF, and a current is intermittently supplied to the logic input circuit 15. That is, since the current is not always supplied to the input circuit 15, heat generation of components mounted on the logic input circuit 15 can be suppressed.

  FIG. 3 is an explanatory diagram of heat generation of the logic input circuit 15, FIG. 3 (a) is an explanatory diagram of the conventional case, and FIG. 3 (b) is an explanatory diagram of the case of the present invention. In the conventional case, as shown in FIG. 3A, since the voltage V of the logic signal is continuously applied to the resistor 20, the current I flows continuously. In the case of the present invention, as shown in FIG. 3B, the voltage V of the logic signal is intermittently applied to the resistor 20 by the intermittent operation of the photoMOS relay 22 of the logic input control circuit 18. The current I flows intermittently. Now, let Q1 be the amount of heat generated by the resistor 20 in the conventional case, and Q2 be the amount of heat generated by the resistor 20 in the present invention.

  FIG. 4 is an explanatory diagram of the current flowing through the logic input circuit 15, FIG. 4 (a) is an explanatory diagram of the conventional case, and FIG. 4 (b) is an explanatory diagram of the case of the present invention. Now, assume that the photoMOS relay 22 is turned ON for a time α in a period of time T. In this case, the arithmetic processing circuit 14 takes in the logic signal during the time α during which the photoMOS relay 22 is ON.

  When a logic signal is read as shown in FIGS. 4A and 4B, a comparison between the prior art and the present invention is shown in equation (1).

<Difference in calorific value between conventional and present invention>
Q1 = V1 · T
Q2 = V1 ・ α
Q2 / Q1 = α / T (1)
In the case of the present invention, the calorific value can be reduced to α / T from the formula (1) as compared with the prior art. According to the embodiment of the present invention, heat generation can be suppressed, so that a small protection control device can be provided.

  FIG. 5 is a circuit diagram of another example of the logic input control circuit and the logic input circuit shown in FIG. Another example shows a case where a plurality of logic signals are input to the logic input circuit 15.

  In FIG. 5, when voltages V1, V2, and V3 of a plurality of logic signals are input to each logic input circuit, by making one side of the logic input circuits of the currents I1, I2, and I3 flowing through the resistors 20 common, It is also possible to collectively control all the logic signals by repeating ON / OFF of the logic input circuit 15 by the photo MOS relay 22 of the logic input control circuit 18.

  According to the first embodiment of the present invention, by intermittently taking in a logic signal from the outside, it is possible to intermittently flow a current flowing from the outside, and to suppress component heat generation of the logic input circuit 15. Can do. Therefore, it is possible to provide a small protection control device without requiring a heat sink for heat dissipation in the logic input circuit 15 and without having a complicated structure such as providing a slit for heat dissipation in the case.

(Second Embodiment)
FIG. 6 is a circuit diagram of an example of a logic input control circuit and a logic input circuit according to the second embodiment of the present invention. In the second embodiment, in contrast to the first embodiment shown in FIG. 2, the logic input circuit 15 includes a constant current diode 23 that converts a logic signal inputted from the outside with a voltage into a constant current. Is.

  In FIG. 6, the logic input circuit 15 is provided with a constant current element 23 for converting a logic signal having an applied voltage into a constant current. That is, the logic signal can be supplied with a constant current even when the logic signal voltage V has a different rating by the constant current circuit using the constant current diode 13.

  7A and 7B are explanatory diagrams of heat generation of the logic input circuit 15. FIGS. 7A and 7B are explanatory diagrams of the conventional case, and FIGS. 7C and 7D are explanatory diagrams of the case of the present invention. is there. In the case of the conventional logic signal having the minimum voltage Vmin, as shown in FIG. 7A, since the voltage Vmin of the logic signal is continuously applied to the resistor 20, the current I flows continuously and the calorific value is Q1min. In the case of the conventional logic signal having the maximum voltage Vmax, as shown in FIG. 7B, the voltage Vmax of the logic signal is continuously applied to the resistor 20, so that N times the current NI flows continuously. The calorific value is Q1max.

  On the other hand, in the case of the present invention, as shown in FIGS. 7C and 7D, even when the logic signal has the minimum voltage Vmin or the logic signal having the maximum voltage Vmax, the constant current element 23 is passed. Therefore, the current I is the same, and the heat generation amount Q2min and the heat generation amount Q2max have a difference corresponding to the voltage of the logic signal.

  That is, assuming that the relationship between the minimum and maximum voltage of the logic signal is expressed by equation (2), the comparison of the heat generation amount between the conventional and the present invention is expressed by equation (3).

<Relationship between minimum and maximum input voltage>
Vmax = N · Vmin (2)
<Difference in heat generation between conventional circuit and constant current circuit>
Q1max = {(N · Vmin) ² / R} · T
Q1min = {(Vmin) ² / R} · T
K1 = Q1max / Q1min = N ²
Q2max = {(N · Vmin) · I} · T
Q2min = {(Vmin) · I} · T
K2 = Q2max / Q2min = N
K2 / K1 = 1 / N (3)
In the case of the present invention, the calorific value can be reduced to 1 / N from the formula (3) as compared with the prior art.

Furthermore, when energized intermittently under the control of the logic input control circuit 18,
Since the current is not always supplied to the logic input circuit 15, the heat generation can be further suppressed. The effect in that case will be described. As an example, the circuit example of FIG. 8 is used, and a comparison of the amount of heat generated in the prior art and the present invention is shown in equation (4).

<Difference in heat generation between the conventional circuit and the circuit of the present invention>
(Q2 / Q1) · (K2 / K1) = α / (N · T) (4)
Further, the logic input control circuit 18 can reduce the amount of heat generation to α / (N · T) compared to the conventional case. According to the second embodiment of the present invention, since it is possible to suppress heat generation, it is possible to provide a small protection control device, and it is possible to deal with a wide range of logic signal voltages with one type of logic input circuit.

(Third embodiment)
FIG. 9 is a block diagram of a protection control apparatus according to the third embodiment of the present invention. The third embodiment is different from the first embodiment shown in FIG. 1 in that a power supply voltage monitoring circuit 24 for monitoring the control power supply voltage supplied from the power supply circuit 19 is provided. Is a circuit that controls the current flowing into the logic input circuit 15 by switching the resistance in the logic input circuit 15 in accordance with the level of the control power supply voltage obtained by the power supply voltage monitoring circuit 24. The same elements as those in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted.

  The power supply voltage monitoring circuit 24 monitors the magnitude of the control power supply voltage applied to the power supply circuit 19, determines the level of the control power supply voltage, and outputs a control signal from the arithmetic processing circuit 14 based on the level determination result to output a logic input circuit. The resistance in 15 is switched to suppress the current flowing in the logic input circuit 15.

  FIG. 10 is a circuit diagram of an example of a logic input control circuit and a logic input circuit according to the third embodiment of the present invention. As shown in FIG. 10, the logic input circuit 15 is input to a plurality of series-connected resistors 25, and a resistance control switch 26 is connected to the resistors 25 in parallel. FIG. 10 shows a case where two resistors 25 are connected in series and a resistance control switch 26 is connected in parallel to one resistor 25.

  When the voltage of the logic signal is high, the arithmetic processing circuit 14 opens the resistance control switch 26 and connects the two resistors 25 in series. Thereby, the current in the logic input circuit 15 is suppressed. On the other hand, when the voltage of the logic signal is small, the arithmetic processing circuit 14 closes the resistance control switch 26 and connects one resistor 25. As a result, the current in the logic input circuit 15 can be reduced even when the voltage of the logic signal changes.

  For example, when the level determination threshold value of the power supply voltage monitoring circuit 24 is 150 V, the resistance control switch 26 of the logic input circuit 15 is turned ON when the control power supply voltage is 110 V, and the resistance of the logic input circuit 15 when the control power supply voltage is 220 V. The control switch 26 is turned off. As a result, the resistor 25 of the logic input circuit 15 is switched, and the energization current can be controlled stepwise even when a wide range of logic signal voltages are applied. Therefore, a common circuit hardware can cope with a wide range of logic signal voltages, and heat generation can be suppressed as compared with the conventional one, so that a small protection control device can be provided.

  According to the third embodiment, the resistance of the logic input circuit 15 is switched from the arithmetic processing circuit 14 in accordance with the control power supply voltage level of the protection control device, and the current flowing into the logic input circuit 15 is controlled. Even when the rated voltage differs for one type of logic input circuit 15 with respect to the logic signal voltage, the protection control device can be shared.

(Fourth embodiment)
FIG. 11 is a circuit diagram of an example of a logic input control circuit and a logic input circuit according to the fourth embodiment of the present invention. The fourth embodiment is shorter than the first embodiment shown in FIG. 2 every time the external contact is closed with respect to the external contact that controls the logic signal of the voltage input to the logic input circuit. An instantaneous current energizing circuit 27 for energizing a large current only for a time is provided. The same elements as those in FIG. 2 are denoted by the same reference numerals, and redundant description is omitted.

  As shown in FIG. 11, an instantaneous current conducting circuit 27 for supplying a large current for a short time each time the external contact is closed is connected in parallel to the input terminal of the logic input circuit 15 with respect to an external contact (not shown) outside the protection control device. Has been. As described above, the external contact is a contact that controls the logic signal voltage input to the logic input circuit 15.

  The instantaneous current conduction circuit 27 is configured by a parallel circuit of a capacitor 28 and a resistor 29. When an external contact (not shown) outside the protection control device is closed and a logic signal voltage is applied to the logic input circuit 15 of the protection control device, current is supplied to the capacitor 28 of the logic input circuit 15 until the capacitor 28 is charged. Flows in. For this reason, a large current flows through the contact portion of the external contact. After the capacitor 28 is charged, the potential difference across the capacitor 28 is equivalent to the level of the logic signal voltage input to the logic input circuit 15. As a result, the logic signal voltage becomes the magnitude of the control power supply voltage of the protection control device of the first embodiment.

  On the other hand, when the external contact is opened, no logic signal voltage is applied to the logic input circuit 15. However, when the capacitor 28 is charged, a current is passed through the logic input circuit 15 until the capacitor 28 is completely discharged. In this way, using the charging / discharging of the capacitor 28 of the instantaneous current energizing circuit 27, a large current is energized for a short time every time the external contact for controlling the logic signal voltage input to the logic input circuit 15 is closed. Therefore, even when an oxide film is generated at the contact portion of the external contact, the oxide film is removed every time the external contact is closed, and the contact failure of the external contact can be prevented, thereby improving the reliability of the entire system.

  In the above description, the case where the instantaneous current energizing circuit 27 that energizes a large current only for a short time each time the external contact is closed is provided with respect to the first embodiment. In contrast to the third embodiment, an instantaneous current conduction circuit 27 may be provided.

  According to the fourth embodiment, every time an external contact outside the protection control device is closed, a large current is passed through the logic input circuit for a short time to control the logic signal voltage input to the logic input circuit 15. Even when an oxide film is generated at the contact portion of the contact, the oxide film is removed every time the external contact is closed, and contact failure of the external contact can be prevented. As a result, the logic signal can be correctly taken into the protection control device.

DESCRIPTION OF SYMBOLS 11 ... Input transformer, 12 ... Input analog circuit, 13 ... A / D conversion circuit, 14 ... Arithmetic processing circuit, 15 ... Logic input circuit, 16 ... Relay output circuit, 17 ... Output contact, 18 ... Logic input control circuit, DESCRIPTION OF SYMBOLS 19 ... Power supply circuit, 20 ... Resistance, 21 ... Photocoupler, 22 ... Photomoss relay, 23 ... Constant current diode, 24 ... Power supply voltage monitoring circuit, 25 ... Resistance, 26 ... Resistance control switch, 27 ... Instantaneous current conduction circuit , 28 ... capacitor, 29 ... resistance

Claims (4)

  In a protection control device that detects a system fault and performs predetermined control according to the current, voltage, phase, and logic signal input conditions of the power system, the current and voltage are input from the power system via the input transformer, and the input transformer An analog conversion circuit that converts a secondary-side signal into an analog signal of a predetermined level, an A / D conversion circuit that converts the analog signal of the analog conversion circuit into a predetermined digital signal, and predetermined operating conditions and output conditions are set A logic input circuit that takes in a logic signal of a voltage from the outside, and performs a predetermined protection control operation based on the digital signal of the A / D conversion circuit and the logic signal of the logic input circuit, and externally via a relay output circuit An arithmetic processing circuit that outputs the result of the protection control calculation, and a voltage logic signal is fetched from the outside in response to a command from the arithmetic processing circuit. A logic input control circuit for intermittently operating the logic input circuit in accordance with the timing, and the input transformer so that the control voltage has the same value as the voltage of the logic signal from the outside of the logic input circuit; A protection control device comprising: the analog conversion circuit; the A / D conversion circuit; and a power supply circuit that supplies a control power supply voltage to the arithmetic processing circuit. The protection control device according to claim 1, wherein the logic input circuit includes a constant current element that converts a logic signal input from an external voltage into a constant current. A power supply voltage monitoring circuit for monitoring a power supply voltage for control supplied from the power supply circuit is provided, and the arithmetic processing circuit is provided in a logic input circuit according to a level of the control power supply voltage obtained by the power supply voltage monitoring circuit. The protection control device according to claim 1, wherein a current flowing into the logic input circuit is controlled by switching a resistor. The logic input circuit includes an instantaneous current energization circuit that energizes a large current only for a short time each time the external contact is closed with respect to an external contact that controls a logic signal of a voltage input to the logic input circuit. The protection control device according to any one of claims 1 to 3.

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