HK1105248A - Device and method for the extended protection of electric lines - Google Patents

Description

Device and method for wire expansion protection

Technical Field

The present invention relates to a device and a method for extended protection of electric wires, which provide innovative characteristics and important advantages more critical than the existing devices and methods for the same purpose in the current state of the art.

More particularly, the present invention relates to an electrical/electronic device and a method of operating the same, designed to provide an electrical line (whether a power supply line or a signal transmission line) with extended protection, including continuous verification of the condition of the electrical line and identification of the cause of a potential abnormal condition thereof.

Background

Electronic and electrical circuits are often supported by safety elements that provide some protection and facilitate recovery of the circuit in the event of a potential overload. However, these circuit safety elements present some drawbacks.

If the circuit is protected by a fuse element (flux plate element), it is difficult to visually distinguish whether the safety element is fused, and the cause of the failure in the circuit or any unit that generates it cannot be determined. The line may even operate at the nominal current limit of the circuit, so that the safety element exhibits a resistance variation, thus preventing the unit it supplies from functioning correctly, but without indicating an anomalous condition of the line.

On the other hand, in circuits protected by other safety elements, such as thermal switches or resettable fuses, the operation of the lever or button for recovery is simple, but such safety elements are also not able to determine the cause of a fault in the circuit or the unit that generated it, which leads to the necessary repeated recovery, causing rapid ageing of the safety element.

Disclosure of Invention

The present invention solves the above problems by providing a wire protection device and method that allows for continuous verification of the condition of a wire and identification of the cause of its potential abnormal condition.

Thus, according to a first embodiment of the present invention, there is provided an electric/electronic protection device for electric wires, connected in parallel with a safety element at the entrance of a unit to be protected, comprising: a processing unit for controlling and functionally connecting the remaining protection device components to each other; a power supply unit for supplying power to the processing unit during an abnormal line condition, at least during a lack of power to the line itself; a voltage measuring unit for measuring an abnormal local voltage; an alarm unit signaling the detected condition of the protection device; and a switching unit for alternately supplying the power of the line itself to the remaining device parts (main branch) or bypassing the power of the line itself from the remaining device parts through the branches (branches) of the device.

The alarm unit may be of various types depending on the action to be performed in the particular application of the invention. As just one example, the alarm unit may simply comprise an array of LED-type annunciators that selectively energize to notify the user of the respective condition of the line being checked, or an LCD-type annunciator that can also provide the user with data on the condition of the line after checking, or may comprise a transmitter that transmits a signal to a remote line monitoring center or the like, or may comprise a combination of these.

In addition, the apparatus of the present invention may further optionally include a load out so that the apparatus is prevented from being short-circuited when the switching unit is in the branch state.

The device of the invention exhibits the feature of being installable in a fixed manner, so as to maintain a fixed (permanent) connection with the line, and of being able to react in real time to accidents, i.e. it allows a continuous check of the safety element and of the unit provided by the connection of the terminal in which it is arranged.

According to a second embodiment of the present invention, there is provided an electric wire protection method including three operation modes according to a line condition:

normal mode of operation: the safety element is in a perfect condition, subject to a strength in the nominal working range; the security element therefore exhibits substantially zero resistance and therefore almost all current flows through the element.

The voltage measuring unit of the protection device does not measure any voltage drop and the protection device remains inactive.

Boundary anomaly mode of operation: the intensity of the current flowing through the safety element rises to the nominal working poleAbove the limit until a predetermined arming threshold is exceeded which causes the temperature to approach that of the security element breakdown or trigger point and hence causes its resistance (the resistance value and duration being design variables, depending on the nominal impedance and other intrinsic line parameters, primarily the maximum power that the emission source can provide) to change.

Thus, part of the current flows to the protection device of the invention and, since the switching unit is in the default state, part of the current is diverted to the main branch. The processing unit receives a signal from the voltage measuring unit, which signal is related to a voltage that can rise until a value at least corresponding to said alarm threshold is reached, and enables a corresponding control signal to the alarm unit.

Line checking abnormal working mode: after a failure (breakdown) or trigger (trigger) of the safety element, the entire current flows through the protection device of the invention and, due to the default state of the switching unit, the entire current is diverted to the main branch.

The processing unit receives a signal from the voltage measuring unit, the signal being related to a voltage which rises until at least a fault point is reached. Thereafter, the processing unit initiates a duty cycle that includes enabling a control signal to the switching units so that they divert current to the branch (the switching units are held in this state using the voltage provided by the currently operating power supply unit), processing the line parameters to check the line condition, enabling a control signal to the alarm unit corresponding to the line condition, and enabling a control signal to the switching units so that they again divert current to the main branch.

If desired, based on the nature and design of the voltage measuring unit, the processing unit enables further control signals to the voltage measuring unit, so that they enter the off mode when the current has to be diverted to the branch.

Drawings

Other features and advantages of the present invention will be more clearly seen from the following detailed description of preferred embodiments, given for purposes of illustration only and not limitation, taken in conjunction with the accompanying drawings, in which

FIG. 1 shows a block diagram of the protection device of the present invention;

fig. 2 shows a circuit diagram of a first embodiment of the protection device according to the invention;

fig. 3 shows a circuit diagram of a second embodiment of the protection device according to the invention.

Detailed Description

With reference to fig. 1, a block diagram is shown illustrating the principle of the protection device according to the invention, which is located in the line safety element F, so that it remains fixedly connected to the line and reacts in real time to accidents, i.e. it allows continuous control of the circuit provided by the safety element F and the connection terminal A, B, said protection device also being connected to the terminal A, B. The protection device will therefore be used as a power supply or connection between a transmission source for a given type of signal and the circuit to be protected.

The protection device comprises a main branch comprising a power supply unit 60, as well as a voltage measurement unit 10 and a processing unit 30 powered by the power supply unit 60. In addition, the processing unit 30 is also provided with an alarm unit 40. In addition, the protection device comprises a branch, which is connected in parallel with the main branch. Both branches, i.e. the main branch and the branch, converge at the switching unit 50.

Reference is now made to fig. 2, which shows a first basic embodiment of the protection device according to the invention. In this embodiment, the power supply unit 60 includes a capacitor C₁The voltage measuring cell 10 comprises a resistance arrangement R1, R₂、R₃The processing unit 30 comprises a microprocessor M₁The alarm unit 40 comprises an LED-type annunciator L1, L2, L3 arrangement.

As can be seen in fig. 2, the switching cell 50 comprises a transistor T1 of the n-channel MOSFET type.

In this embodiment, if the current through the safety element F (not shown for simplicity of illustration) located between the terminals A, B of the protection device is within the normal operating range, the safety element F exhibits substantially zero resistance and therefore nearly all of the current flows through it. The protection device does not receive any current and remains inoperative.

On the other hand, if the current through the security element rises above the alarm threshold (predetermined by the voltage drop Vu across said security element) and the security element resistance changes and therefore exhibits a certain resistance, part of the current reaching the terminal A, B will flow to the protection device and due to the transistor T₁Is open, the amount of current will flow through the main branch of the protection device, i.e. through the resistive arrangement R₁，R₂，R₃. Then, the microprocessor M₁Will be provided with a signal which will interpret the signal as a boundary abnormal operating condition and will in turn enable a signal to the corresponding annunciator L indicating the indicated condition₁。

Finally, if the current through the safety element rises above the point of failure (breakdown or triggering) of the safety element (by the voltage drop V across said safety element)_RPredetermined), nearly all current flows to the protection device according to the invention and due to the transistor T₁Is open, so that said current will flow through the main branch of the protection device, i.e. through the resistive arrangement R₁，R₂，R₃Additionally providing a capacitor C₁And (6) charging.

Then, the microprocessor M₁Will be provided with a signal which will interpret the signal as a line check abnormal operating condition and will in turn enable a signal to the corresponding annunciator L indicating the condition₂And enabling a signal to the transistor T₁And then will continue to be in the saturation region (on state).

In the transistor T₁During the conducting state (e.g., 100 mus) due to the slave capacitor C₁Received power, so that the microprocessor M₁The processing of the measurement of the supplied signal will be maintained due to the transistor T₁Is in a conducting state, so that the capacitor C₁Will continue to be in a discharged state.

During this 100 mus period, the microprocessor M₁The line parameters are analyzed and if the analyzed parameters indicate a short circuit of the line, the microprocessor M₁Will also enable a signal to the corresponding annunciator L₃L3 will be switched on after a period of 100 mus.

When this 100 mus ends, the microprocessor M₁Discontinuing the signal to said transistor T₁Then transistor T₁Returning to the open state, the current is again made to flow through the main branch of the protection device.

When this point is reached, the microprocessor M₁Will be programmed to enable this signal to the transistor T periodically during 100 mus₁At least a predetermined number of times to maintain a continuous line check.

Obviously, the signal goes to the transistor T₁Is set to 100 mus as an example in this embodiment and the signal is applied to the transistor T₁And the signal to the transistor T₁Will be calibrated on the basis of the line design parameters to prevent damage to the line and its power providing units.

Referring now to fig. 3, in which like parts have like reference numerals to those in fig. 2, there is shown a second alternative embodiment of a protective device according to the present invention.

In view of the development of the first embodiment described in detail herein, and in order to avoid repetition, specific features of the second embodiment will be described hereinafter with occasional reference to the first embodiment.

In particular, the second embodimentExample in the first embodiment, a rectifier D is added₁So that the protective means can be used regardless of the polarity of the line, the rectifier D₁A diode bridge circuit connected to the terminals a, B and to the main branch of the protection device. The configuration process of rectifiers is well known in the art and there are many technically equivalent variations.

The second embodiment adds a second transistor T to the first embodiment, optionally or in addition to the rectifier₂Of which and T₁The case being the same as the n-channel MOSFET type, with a transistor T₁Are arranged symmetrically. The transistor configuration T₁，T₂And constitute the switch unit in this embodiment.

Furthermore, the second embodiment adds an alternative main branch to the first embodiment, which directly interconnects the terminals a, B with an additional voltage measuring device L in between_1’And L_1”(also used as a further alarm unit in this case) and a disconnection unit S₁。

The alternative main branch ensures that the protection device in the second embodiment operates normally together with the highly sensitive safety element, i.e. the safety element exhibiting a relatively low resistance up to the point of failure. In this case, the main branch may exhibit a high load associated with the maximum load in the safety element (just before the point of failure), so that a greater part of the current flowing to the protection device during a marginal abnormal operating condition may be insufficient for the microprocessor M₁And (6) working.

In this embodiment, the additional voltage measurement unit comprises an LED-type annunciator L_1’And L_1”Which act as additional alarm units and which, if they are arranged in an alternative main branch, which is part of the protection device as shown in the first embodiment, would comprise a single LED-type annunciator suitably set in view of the polarity of the line, and said disconnection unit S₁In this embodiment a normally closed relay is included.

Considering a rectifier D₁Transistor arrangement T₁、T₂And the presence of an alternative primary branch, in a second embodiment, the operation is as follows:

normal operation (V)_AB0): the safety element exhibits substantially zero resistance, so that almost all the current flows through the element, and the protection device does not receive any current and remains inactive.

Boundary abnormal operation (V)_U＜|V_AB|＜V_RIn which V is_UIs a voltage, V, corresponding to the above-mentioned warning threshold_RIs the voltage corresponding to the breakdown point of the security element): the security element exhibits a certain resistance and part of the current reaching terminal A, B will flow to the protection device. Due to the transistor T₁And T₂Is open, so the relay S₁Is on, the load of the main branch is high with respect to the load of the safety element, said amount of diverted current flowing through the alternative main branch of the protection device, i.e. through the LED-type signaller L_1’And L_1”And (4) configuring. Corresponding annunciator L_1’And L_1”Is activated, the microprocessor M₁And remain inoperative.

Linear check for abnormal operation (V)_AB> 0 and | V_AB|＞V_RIn which V is_RIs the voltage corresponding to the security element breakdown point): all current flows through the protection device of the invention and due to the transistor T₁And T₂Is open, said current being split between the primary branch and the alternative primary branch of the protection device. The current flowing through the main branch is now sufficient to activate the microprocessor M₁To send a turn-on signal to the relay S₁. Thus, the full current will then flow through the main branch, i.e. through the resistive arrangement R₁，R₂，R₃And additionally to a capacitor C₁And (6) charging. Then, the microprocessor M₁Will be supplied from the resistance arrangement R₁，R₂，R₃A signal which interprets said signal as a line check for abnormal operating conditions and will in turn enable a signal to the indicating meansCorresponding annunciator L of the condition₂And enabling a signal to the transistor T₁And T₂Said transistor T₁And T₂Will continue to be in the on state. Due to the transistor T₁And T₂Are symmetrically oppositely arranged, so T₁Will only allow the passage of current through it, but T₂Will be converted to a resistance so that the overall operation is similar in all other respects to the first embodiment.

Linear check for abnormal operation (V)_AB< 0 and | V_AB|＞V_RIn which V is_RIs the voltage corresponding to the security element breakdown point): all current flows through the protection device of the invention and due to the transistor T₁And T₂Is open, so the current is split between the primary branch and the alternative primary branch of the protection device. The current flowing through the main branch is now sufficient to activate the microprocessor M₁To send a turn-on signal to the relay S₁. In this way, all current will then flow through the main branch, i.e. through the resistive arrangement R₁，R₂，R₃Additionally providing a capacitor C₁And (6) charging. Then, the microprocessor M₁Will be provided with a signal from the resistance arrangement R₁，R₂，R₃Will interpret said signal as a line check abnormal operating condition and will in turn enable a signal to the corresponding annunciator L indicating said condition₂And enabling a signal to the transistor T₁And T₂Said transistor T₁And T₂Will continue to be in the on state. Due to the transistor T₁And T₂Symmetrically opposite of each other, T₂Will only allow the passage of current through it, but T₁Will be converted to a resistance so that the overall operation is similar in all other respects to the first embodiment.

For both the embodiment of fig. 2 and the embodiment of fig. 3, it will be understood by those skilled in the art that, depending on the particular application of the protective device, generally enough components must be provided for the device to function well.

In this sense, as a non-limiting example only, a conventional voltage regulation unit, such as a Zener-type diode, placed in parallel with capacitor C1, may be added to capacitor C1.

Also, specifically, in the second embodiment, in the microprocessor M₁Can configure the transistor with T during the initial stabilization period₁And T₂Increasing and decreasing transistor T₁Or T₂Gate-source voltage (depending on the line polarity).

Similarly, for both the embodiment of FIG. 2 and the embodiment of FIG. 3, V will be understood by those skilled in the art_UAnd V_RCan be determined from the line parameters and the required safety level, V_UFor applications with high safety and/or high sensitivity is practically zero.

Naturally, the principle of the invention remaining the same, the embodiments and construction details may be varied widely with respect to the above description and examples without departing from the scope of the invention.

These changes will affect the shape, size, and/or materials of manufacture of the physical components of the device, and of course, the implementation characteristics of the required software.

For exemplary purposes only, the following examples may be cited.

As already mentioned, the alarm unit may simply comprise an array of LED-type annunciators, the selective activation of which informs the user of the respective condition of the line being checked, as in the described embodiment, or may comprise an LCD-type annunciator which additionally informs the user of the line condition being checked, or may comprise a transmitter which transmits a signal to a remote line monitoring center or the like, or may even comprise a combination of these several units.

Also, the processing unit may comprise a microprocessor, as described in the embodiments, or may comprise equivalent analog circuitry, or may comprise analog circuitry specifically designed for a particular application.

Also, the entire device or portions may be fabricated in an integrated circuit chip.

Naturally, if the microprocessor is used for any task, its internal software will depend on the specific application and the corresponding specific design parameters for the line.

Further, the power supply unit may include a capacitance unit, as described in the embodiment; or may comprise an external power source, such as a battery, in addition to or instead of the capacitive unit.

Finally, designs within the scope of the invention may include a plurality of the protection devices of the invention sharing a single set of processing units to protect a corresponding plurality of secure elements with their respective circuits.

Claims (16)

1. A device for protection of electric lines, arranged at the inlet of a unit to be protected in parallel with a safety element (F), characterised in that it comprises

a) A processing unit (30) controlling and functionally interconnecting the remaining device components;

b) a power supply unit (60) which supplies power to the processing unit (30) during abnormal line conditions, at least during the absence of power from the line itself;

c) a voltage measurement unit (10) that measures an abnormal local voltage;

d) a unit (30) for generating an alarm signal reflecting the condition detected by the protection device; and

e) a switching unit (50) which alternately supplies the power of the line itself to the remaining device components (main branch) or avoids the power of the line itself from the remaining device components through the branch (branch) of the protection device.

2. The wire protection device according to claim 1, further comprising an alarm unit (40) which optically signals the detected condition of the protection device in response to said alarm signal.

3. The wire protection device of claim 1, wherein it is mounted by a fixed manner.

4. The wire protection device of any preceding claim, including a load disposed outside the main branch.

5. The wire protection device according to any one of the preceding claims, characterized in that said alarm unit (40) comprises at least one LED-type annunciator and/or at least one LCD-type visual device and/or a transmitter arrangement.

6. The wire protection device according to any one of the preceding claims, wherein the processing unit (30) comprises an analog circuit or a microprocessor.

7. The wire protection device according to any one of the preceding claims, wherein the power supply unit (60) comprises:

a) a capacitive unit, preferably comprising a capacitor; or

b) A capacitor unit, preferably comprising a capacitor and a voltage stabilizing unit, preferably comprising a zener diode; and/or

c) The external power source, preferably comprises a battery.

8. The wire protection device according to any one of the preceding claims, wherein the voltage measuring unit (10) comprises a resistive arrangement.

9. The wire protection device according to any one of the preceding claims, wherein the switching unit (50) comprises:

a) at least one transistor, preferably of the n-channel MOSFET type; or

b) A relay.

10. The line protection device according to any one of the preceding claims, comprising a rectifier (D1), preferably a diode bridge circuit, to ensure a constant polarity of the protection device.

11. The electric wire protection device according to any one of claims 1 to 7, wherein the switch unit includes:

a) first and second n-channel MOSFET-type transistors arranged symmetrically in series so that their gates are connected to each other and to the processing unit, their drains are directly connected to each other and are connected in said main branch at one end to a switching unit (50) and at the other end to two terminals of the protection device through a rectifier; and

preferably, the switching unit (50) further includes:

b) diode bridge circuits as rectifiers.

12. The wire protection device according to any one of the preceding claims, comprising an alternative main branch comprising a disconnection unit, preferably a relay, and an additional voltage measurement unit (10), the additional voltage measurement unit (10) preferably comprising an additional alarm unit, preferably comprising at least an LED-type annunciator, connected to said processing unit (30).

13. The electrical wire protection device according to any one of the preceding claims, wherein the processing unit (30) is shared with other protection devices according to any one of the preceding claims.

14. The wire protection device of any preceding claim, wherein at least part of the protection device is fabricated in an integrated circuit chip.

15. Method for protecting electric lines by means of a protection device according to any one of the preceding claims, characterized in that it comprises three modes of operation depending on the line conditions:

a) a normal operating mode, in which the safety element (F) is in an intact condition, subject to a strength in the nominal operating range; the safety element (F) therefore exhibits a substantially zero resistance and therefore almost the entire current flows through this element (the voltage measuring unit (10) of the protection device does not measure the voltage drop and the protection device remains inactive);

b) a boundary abnormal operating mode, in which the intensity of the current flowing through the safety element (F) rises above the nominal operating limit until a predetermined warning threshold is exceeded, which causes the temperature to approach that of the safety element breakdown point or trigger point and therefore causes a change in its resistance (therefore, part of the current flows towards the protection device and, since the switching unit is in the default state, all the current is diverted to the main branch, in which the processing unit (30) receives a signal from the voltage measuring unit (10), which is correlated with a voltage that rises until a value at least corresponding to said warning threshold is reached, and which enables a corresponding control signal to the alarm unit);

c) the line checks for an abnormal operating mode in which, after a failure (breakdown or triggering) of the safety element, all the current flows through the protection device, and since the switching unit is in the default state, the entire current is diverted to the main branch, wherein the processing unit (30) receives the signal from the voltage measuring unit (10), the signals are related to a voltage which rises until at least a fault point is reached, after which they start a working cycle, the duty cycle includes enabling a control signal to the switching units (50) so that they divert current to the branch (the switching units are held in this state using the voltage supplied by the currently operating power supply unit (60)), processing line parameters to check the line condition, enabling a control signal to an alarm unit (40) corresponding to the line condition, and enable a control signal to the switching units (50) so that they again divert the current to the main branch.

16. The method of claim 15,

a) said processing unit (30) enabling a further control signal to the additional voltage measuring units (10) so that they enter a disconnected state when current has to flow to the branch; and/or

b) The processing unit (30) is programmed to periodically form the duty cycle; and/or

c) -said processing unit (30) is programmed to maintain said switching unit (50) for a period of about 100 μ s per duty cycle by diverting the current to the branch; and/or

d) The processing unit (30) is programmed so that the alarm unit (40) remains continuously activated during the entire line check abnormal mode of operation, regardless of the time of the cycle of operation, signaling the line status.