High-frequency anti-interference ground fault circuit interrupter and GFCI circuit

Abstract

The utility model provides a high-frequency anti-interference ground fault circuit interrupter and a GFCI circuit, which have an end-of-life self-checking function and comprise a high-frequency GFCI. The high frequency GFCI includes a circuit breaker and a relay circuit for controlling the circuit breaker. The high-frequency GFCI further comprises a fault detection circuit and a latch circuit. The utility model also provides an isolation circuit used for isolating the latch circuit and the fault detection circuit during a self-test period. And the self-checking circuit is used for testing the latch circuit and the fault detection circuit. An end-of-life circuit is also provided for disabling the high frequency GFCI when a self-test fails.

Description

Technical Field

[0001] This utility model generally relates to electrical safety equipment, and more specifically, to a high-frequency anti-interference grounding fault circuit interrupter, which has a life-end self-test circuit. Background Technology

[0002] Traditional electrical appliances typically receive alternating current (AC) from a power source (such as a power outlet) via a pair of conductive wires. These conductive wires are usually called the phase wire and the neutral wire, which allow the appliance or load to receive the current necessary for its operation.

[0003] When an electrical appliance is connected to a power source via a pair of conductive lines, several potential hazardous conditions can arise. The following risks exist in the conductive lines: ground fault, neutral grounding, and open neutral circuit. A ground fault occurs when there is an imbalance in the current flowing in the phase and neutral lines. A neutral grounding occurs when the neutral line is grounded at the load end. An open neutral circuit occurs when the neutral line between the load and the power source is open.

[0004] Ground fault circuit interrupters (GFCIs) are well known in the art and are commonly used to prevent ground faults, neutral grounding, and open neutral conditions. A GFCI device senses a ground fault or neutral grounding condition in a conductive line and, in response, opens at least one conductive line between the power source and the load to eliminate the hazardous condition.

[0005] A typical ground fault interruptor includes an operational amplifier that amplifies the sensed ground fault signal and applies the amplified signal to a window comparator, which compares the amplified signal to positive and negative reference signals. If either reference value is exceeded, a trip signal is generated. A common type of ground fault detection circuit is a dormant oscillator detector. This detector includes a first sensor coil through which the phase and neutral lines of the protected circuit pass. The output of the first sensor coil is applied to the aforementioned operational amplifier via a coupling capacitor, followed by the window comparator. A line-to-ground fault causes the amplified signal to exceed the reference value, generating a trip signal.

[0006] Ground fault interrupters include ground fault circuit breakers, ground fault sockets, and even ground fault protection devices installed on power lines. Even if ground fault interrupters have met all current industry standards, they can still be prone to false tripping. One cause of false tripping may be disconnecting the power supply to inductive appliances, especially by unplugging them.

[0007] Examples of such appliances include electric shavers, high-intensity lights, and small cooling fans (such as those used to cool electronic devices). Unplugging these appliances can create an electric arc between the plug and socket, resulting in several volts of broadband noise superimposed on the power line. Due to the broadband nature of the noise, even small stray coupling capacitances can couple the noise from the power line conductors into a ground fault circuit, causing false tripping.

[0008] It has been found that broadband noise pulses caused by load-related switching phenomena (such as from unplugging inductive appliances) can lead to false tripping of typical ground fault interrupters. Broadband noise pulses typically contain frequency components ranging from greater than 60 Hz to 150 kHz.

[0009] Another possible cause of a typical GFCI tripping error is due to the typical construction of appliances (such as washing machines, refrigerators, or air conditioners), which are equipped with variable speed drives, electronic circuits, and / or frequency converters. These devices often exhibit high-frequency (e.g., greater than 60 Hz) leakage currents that flow through the grounding conductor of the appliance's power line and into the building's electrical system.

[0010] Another drawback of typical GFCI devices is that they generally include large solenoids used to selectively turn the switching device on and off. Specifically, the solenoid typically requires a constant supply of line voltage (approximately 120 volts) to switch and maintain its energized state. Therefore, the solenoid is a significant source of power consumption.

[0011] Furthermore, the UL 943 standard requires that panel-mounted and outlet-based GFCIs, when manually operated with a test button, should indicate "end of life" if the GFCI device fails to trip. However, even if end users regularly test their devices, an improperly tested GFCI device may still reset and continue supplying power instead of providing ground fault protection. Without a built-in power rejection feature, consumers may unfortunately mistakenly assume that as long as there is power, there is protection. Despite manufacturer warnings, many end users are unaware of the necessity of regular testing (and still are); while others, while aware of the need for regular testing, are not always diligent in performing it.

[0012] End-of-life event test: Ground fault sensing components (magnetic ring and integrated circuit) are open or short-circuited; trip solenoid and / or its control circuit is faulty; or the switching semiconductor (SCR) controlling the trip solenoid control circuit is open or short-circuited.

[0013] Therefore, a solenoid with sufficient ratings to meet the requirements of line voltage GFCI devices is needed, while also reducing the likelihood of failures due to the high voltage and current associated with typical line voltages. A ground fault interrupter is also needed that does not trip falsely due to broadband noise in the protected circuit. Furthermore, GFCI devices with improved immunity to broadband signals and / or frequency components greater than 60 Hz are also required.

[0014] We also need a GFCI that can perform manual and automatic testing on frequently failing components within the GFCI, and if the automatic test fails, it can refuse power or perform a life-end switching. Utility Model Content

[0015] The purpose of this invention is to provide a novel and improved GFCI.

[0016] Another object of this invention is to provide a GFCI that senses ground faults and neutral grounding conditions in a conductive line, and in response thereto includes a solenoid that opens at least one conductive line between a power source and a load.

[0017] A high-frequency interference immunity ground fault circuit interrupter (GFCI) with a life-end self-test function is provided to interrupt current flowing through a pair of lines. One of the lines extends between a phase input and a phase output, and the other extends between a neutral input and a neutral output. The GFCI includes a high-frequency ground fault circuit interrupter (GFCI) comprising: a first switch having a first input terminal and a first contact terminal; a second switch having a second input terminal and a second contact terminal; and at least one relay circuit for controlling the first and / or second switches. Each switch has a de-energized first position and an energized second position, wherein the first switch is connected between the phase input and the phase output, and the second switch is connected between the neutral input and the neutral output. The GFCI also includes a fault detection circuit for detecting ground faults at either the phase or neutral output. The fault detection circuit includes a sensing transformer for sensing ground faults at either the phase or neutral output. To eliminate high-frequency crosstalk and subsequent improper high-frequency tripping, the fault detection circuit does not include a second sensing transformer. The fault detection circuit also includes an electronic latch-up circuit for de-energizing the relay circuit upon fault detection. It also includes a test module integrated with a high-frequency GFCI. The test module includes: a simulated ground fault generator for simulating ground faults; an automatic monitoring logic module; a relay synchronization switch; and a life-end switch for disabling the at least one relay circuit. It also includes a power supply circuit connected to the phase line input for powering the test module, the first bistable electronic latch-up circuit, the fault detection circuit, and the relay circuit. It also includes a common neutral line connected to the neutral line input and the test module, the first bistable electronic latch-up circuit, the fault detection circuit, the relay circuit, and the power supply circuit, wherein an open-circuit state at the neutral line input places the first and second switches in a first, de-energized position.

[0018] A GFCI circuit is also provided for interrupting current flowing through a pair of lines, wherein one of the lines extends between a phase input and a phase output, and the other extends between a neutral input and a neutral output. The GFCI circuit includes at least one relay-controlled switch disposed between the input and output lines. The GFCI circuit includes an automatic test module for automatically testing and detecting end-of-life conditions. The automatic test module includes: a simulated ground fault generator for simulating ground faults; an automatic monitoring logic module; a relay synchronization switch; and a end-of-life switch for disabling the GFCI circuit if it fails the automatic test. The automatic test module also includes a common neutral line connected to the neutral input, wherein an open-circuit condition at the neutral input de-energizes the relay-controlled switch and interrupts current flow between the input and output lines.

[0019] Preferably, the GFCI circuit further includes a relay circuit for controlling the first switch and / or the second switch, wherein the relay synchronization switch synchronizes the relay circuit with the generated ground fault signal to keep the relay circuit in the energized position during the generation of the ground fault signal.

[0020] Preferably, the GFCI circuit further includes a relay circuit for controlling the first switch and / or the second switch, wherein the life-end switch is operable in response to a signal from the automatic monitoring logic module to return the relay circuit to the power-off position.

[0021] This utility model also relates to a high-frequency interference immunity ground fault circuit interrupter, which has a life-end self-test function for interrupting the current flowing through a pair of lines, wherein one of the pairs of lines extends between a phase input terminal and a phase output terminal, and the other line extends between a neutral input terminal and a neutral output terminal. The high-frequency interference immunity ground fault circuit interrupter includes a GFCI, which includes: a first switch having a first input terminal and a first contact terminal; a second switch having a second input terminal and a second contact terminal; and at least one relay circuit for controlling the first switch and / or the second switch. The GFCI includes a fault detection circuit for detecting a ground fault at the phase output terminal or a neutral ground fault on the GFCI load side. The fault detection circuit includes a sensing transformer for sensing a ground fault or a neutral ground fault on the GFCI load side. To eliminate high-frequency crosstalk and subsequent improper high-frequency tripping, the fault detection circuit does not include a second sensing transformer. The GFCI includes an electronic latching circuit for de-energizing the relay circuit when a ground fault is detected. The GFCI also includes a test module for self-testing. The test module includes: a simulated ground fault generator for simulating ground faults; an automatic monitoring logic module; a relay synchronization switch; and a life-end switch for de-energizing the relay circuit in case of self-test failure. The GFCI also includes a power supply circuit connected to the phase input for powering the test module, electronic latching circuit, fault detection circuit, and relay circuit. The GFCI also includes a common neutral line connected to the neutral input and the test module, electronic latching circuit, fault detection circuit, relay circuit, and power supply circuit. An open-circuit condition at the neutral input de-energizes the relays and opens the first and second switches.

[0022] This invention also includes an automatic monitoring logic module that measures a predetermined number of faults in the GFCI circuit in response to a simulated ground fault signal to test the GFCI circuit. When the predetermined number of faults exceeds a predetermined threshold, the GFCI circuit shuts down. The GFCI circuit under test includes: a sensing transformer; a GFCI integrated circuit (IC) coupled to the sensing transformer; and an electronic latching circuit.

[0023] The following description will present further objects, features, and advantages of the present invention, some of which will be obvious from the description or may be learned by practicing the invention. Reference will be made to the accompanying drawings, which form part of the description and illustrate specific embodiments for practicing the invention. These embodiments will be described in sufficient detail to enable those skilled in the art to practice the invention. It should be understood that other embodiments may be used and structural changes may be made without departing from the scope of the invention. The following detailed description should not be considered limiting, and the scope of the invention is preferably defined by the appended claims. Attached Figure Description

[0024] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various embodiments of the present invention, and together with the specification, explain the principles of the present invention. In the drawings, the same reference numerals denote the same parts:

[0025] Figure 1 This is a schematic circuit diagram of the automatic reset type high frequency anti-interference grounding fault circuit interrupter of this utility model, which has reduced solenoid operating power and life end self-test (STEOL) function.

[0026] Figure 2 This is a schematic diagram of an alternative embodiment of the automatic reset type high frequency anti-interference grounding fault circuit interrupter of the present invention, which has a life end self-test function.

[0027] Figure 3 This is a schematic diagram of an alternative embodiment of the automatic reset type high-frequency anti-interference ground fault circuit interrupter of this utility model, which has selectable 120 / 240 volt operation and end-of-life self-test function; and

[0028] Figure 4 This is a schematic diagram of an alternative embodiment of the manually reset type high-frequency anti-interference grounding fault circuit interrupter of this utility model, which has a life-end self-test function. Detailed Implementation

[0029] The following simplified definitions of the terms will apply throughout the application:

[0030] The term "including" means including but not limited to, and should be interpreted in the manner in which it is typically used in the patent context.

[0031] The phrases “in one embodiment” and “according to one embodiment” generally mean that a particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present invention, and may be included in more than one embodiment of the present invention (these phrases do not necessarily refer to the same embodiment).

[0032] If the instruction manual describes something as "exemplary" or "example," it should be understood as referring to a non-exclusive example.

[0033] If the specification states that a component or feature "may," "can," "may," "should," "preferred," "possibly," "usually," "optionally," "for example," or "probably" (or other such language) be included or have a certain characteristic, then that particular component or feature is not required to be included or have that characteristic.

[0034] High frequency can be defined as greater than 60Hz up to 150kHz.

[0035] Grounding fault conditions can be defined as grounding fault, neutral grounding, and neutral open circuit.

[0036] Now refer to the attached diagram, or more specifically, refer to... Figure 1 It shows a ground fault circuit interrupter (GFCI) circuit constructed according to the teachings of this utility model, which is generally indicated by reference numeral 11.

[0037] After the L input terminal is initially connected to the L load terminal and the N input terminal is initially connected to the N load terminal, the GFCI circuit 11 will automatically protect the load from ground fault conditions. Furthermore, once the GFCI circuit 11 has protected the load from ground fault conditions, it can be reset using a reset switch.

[0038] The GFCI circuit 11 includes a circuit breaker 10, a relay circuit 15, a power supply circuit 13, a boost circuit 19, a fault detection circuit 29, a bistable electronic latch circuit 23, a filter circuit 25, an indicator circuit 18, and a trip indicator circuit line 55. The GFCI circuit 11 also includes a test module 28. This test module 28 includes a relay synchronization switch 31, a self-test circuit 33, a life-end circuit 35, and a life-end switch 35A. It should be understood that these circuits are powered via line 45N through the power input line L and the return line N. It can also be further understood that an open neutral line on the input side of the GFCI circuit 11 disables the solenoid SOL1, which prevents line voltage from being applied to the output load.

[0039] Circuit breaker 10 includes a pair of single-pole double-throw switches SW1 and SW2, located in the phase and neutral lines between the power source and the load, respectively. Circuit breaker 10 is used to selectively open and close this pair of conductive lines. Switches SW1 and SW2 can be in either of two connection positions. In the first connection position (e.g., Figure 1 (As shown), switches SW1 and SW2 are positioned such that the input power supply is not connected to the load, but instead connected to the boost circuit 19. In the second connection position, i.e. with Figure 1 In the opposite positions shown, switches SW1 and SW2 are positioned such that the input power supply is connected to the load, but not to the boost circuit 19.

[0040] It should be understood that these circuits are powered via line 45N through power input line L and return line N. It is also understood that an open neutral line on the input side of GFCI circuit 11 disables SOL1, which prevents SW1 and SW2 from entering their second connection state.

[0041] Relay circuit 15 selectively positions switches SW1 and SW2 in a first connection position or a second connection position. Relay circuit 15 includes solenoid SOL1, transistors Q1 and Q4, diodes D25 and D26; and a bias circuit including resistor R4, Zener transistor D28 and reset switch 15A.

[0042] Solenoid SOL1 is connected to the circuit breaker contacts of switches SW1 and SW2, and is responsible for selectively controlling the connection positions of switches SW1 and SW2. Before power is supplied to GFCI circuit 11, solenoid SOL1 places switches SW1 and SW2 in the first connection position shown in the figure. When solenoid SOL1 is energized, it positions switches SW1 and SW2 in the second connection position.

[0043] The specific construction of the solenoid SOL1 in this invention is unique to GFCI devices. Compared to most solenoids used in existing GFCI devices, SOL1 is much smaller and requires less power. Specifically, the coil resistance of solenoid SOL1 is approximately 5,000 ohms. Due to the unique construction of solenoid SOL1, the line voltage (approximately 120 volts RMS) must be supplied directly to solenoid SOL1 via boost circuit 19 in order to initially energize it.

[0044] The boost circuit 19 provides a temporary voltage sufficient to initially energize solenoid SOL1 from its de-energized state. The boost circuit 19 includes silicon rectifiers D15 and D16 and a surge-limiting resistor R18. Rectifiers D15 and D16 are preferably IN4007, converting AC to DC in the power supply line. When switch SW1 is in its first position and power is supplied to GFCI circuit 11, rectifiers D15 and D16 provide a momentary DC voltage (averaging approximately 126V DC) to solenoid SOL1, energizing it and causing solenoid SOL1 to shift switches SW1 and SW2 to their second connected positions. When switches SW1 and SW2 are shifted to their second connected positions, diode D16 and resistor R18 of the boost circuit 19 are disconnected from the power supply line.

[0045] Once powered on, a minimum constant voltage of approximately 28 volts DC must be supplied to solenoid SOL1 to keep it energized. Boost circuit 19 provides the line voltage to initially drive solenoid SOL1 from its de-energized state to its energized state, and the power supply circuit provides the minimum constant voltage to maintain solenoid SOL1 in its energized state. Capacitor-type power supply circuit 13 provides approximately 37 volts DC (average). The reduction in the voltage required to maintain solenoid SOL1 in its energized state (approximately 83 volts) significantly reduces the power consumption of SOL1 in circuit 11 and reduces heat buildup that would shorten the lifespan of solenoid SOL1.

[0046] The transistors Q1 and Q4 in relay circuit 15 are, for example, MMBTA41 high-voltage transistors, used to control the current flowing through the energized solenoid SOL1. When transistors Q1 and Q4 are "off", current is prevented from flowing through solenoid SOL1, and solenoid SOL1 is de-energized. When transistors Q1 and Q4 are "on", current flows through solenoid SOL1, and solenoid SOL1 is energized.

[0047] Power supply circuit 13 supplies power to GFCI circuit 11. Power supply circuit 13 includes rectifier diodes D7 and D15, voltage drop resistors R9 and R21, and capacitors C11 and C11A. It should be understood that the combined reactance of capacitors C11 and C11A limits the current flowing through rectifiers D7 and D15.

[0048] Silicon rectifiers D7 and D15 convert alternating current from the power supply line to direct current. Voltage drop resistors R9 and R21 limit the constant input voltage supplied to solenoid SOL1. Capacitors C11 and C11A can be any suitable values ​​and help limit the current flowing through rectifiers D7 and D15 and the constant voltage supplied to solenoid SOL1. It should be understood that the goal of the capacitor-powered circuit layout is to reduce heat buildup in the enclosed space, optimize the energy of the SOL1 relay coil to significantly increase the relay contact force, and provide GFCI with a smaller, more robust, and higher product performance.

[0049] The power supply circuit 13 also includes a diode D17 for supplying power to the rest of the GFCI circuit 11.

[0050] Still referencing Figure 1 When switches SW1 and SW2 are in their second connected position, fault detection circuit 29 detects ground faults, neutral grounding, and neutral open circuit conditions in the conductive lines. Fault detection circuit 29 includes sensing transformer T1, coupling capacitor C7, noise suppression capacitor C8, feedback resistor R3, resistor RD, and ground fault interrupter integrated circuit (IC) U1.

[0051] The sensing transformer T1 senses the current difference between the phase line and the neutral line, and in the event of a ground fault (e.g., neutral line grounding and / or leakage current in the load-side line of GFCI circuit 11), the transformer T1 induces a relevant output from its secondary winding. It should be understood that by using only one sensing transformer, high-frequency (e.g., greater than 60 Hz) improper tripping, which is caused by high-frequency crosstalk between the two sensing transformers used in a typical GFCI circuit, is eliminated.

[0052] Integrated circuit U1 is the FM2145 low-power ground fault interrupter circuit. However, it should be understood that any suitable integrated circuit can be used. Integrated circuit U1 amplifies the fault signal generated by transformer T1 and generates an output pulse at pin 5 to activate latch-up circuit 23.

[0053] Upon detecting a ground fault or a ground fault on the load side of GFCI circuit 11, integrated circuit U1 generates an output pulse at pin 5 to activate latch-up circuit 23. The activated latch-up circuit 23 disables or de-energizes solenoid SOL1. Latch-up circuit 23 includes a silicon controlled rectifier SCR1 that can operate in either a conductive or non-conductive state, a noise suppression capacitor C2, and a reset switch 15A.

[0054] In its conductive state, rectifier SCR1 turns off transistors Q1 and Q4 in relay circuit 15 via isolation circuit 31, which will be discussed in more detail here. Noise suppression capacitor C2 prevents rectifier SCR1 from igniting due to electrical noise in circuit 11 in its non-conductive state. Reset switch 15A is a conventional push-in switch. When reset switch 15A is pressed, the sustaining current from the anode of rectifier SCR1 is short-circuited, causing rectifier SCR1 to turn off in its conductive state.

[0055] Resistor R2 and capacitor C13 act as a filter circuit to smooth the varying DC voltage from the power supply via test module 28 and provide a filtered DC voltage to the power input of integrated circuit U1. Capacitor C13 also provides temporary IC VCC when GFCI circuit 11 is in auto-test mode.

[0056] Test circuit 27 provides a means of testing GFCI circuit 11. Test circuit 27 includes a current-limiting resistor R12 and a test switch SW3 of conventional push-in design. When SW3 is pressed to energize test circuit 27, resistor R12 provides a simulated fault current flowing through transformer T1 via test lead 55.

[0057] When a load is plugged into the power supply, if the power is interrupted, solenoid SOL1 will be de-energized, causing switches SW1 and SW2 to return to their first connected position. When power is restored, solenoid SOL1 will be energized again, causing switches SW1 and SW2 to shift to their second position. It is also understood that an open neutral line on the input side of GFCI circuit 11 disables SOL1, thus preventing line voltage from being applied to the output load.

[0058] Indicator circuit 18 provides a visual signal to indicate that the GFCI is operating normally and has not tripped due to a ground fault or neutral grounding condition. Indicator circuit 18 includes diodes DA and D29, a light-emitting diode (LED), and a current-limiting resistor R20. Diode D29 half-wave rectifies the AC power from the line into a pulsed DC power supply for the LED. In the uninterrupted state, the line voltage L is half-wave rectified by the rectifier diode and applied to turn on the LED. If circuit 11 senses a ground fault condition, SOL1 is de-energized, thereby cutting off the power supply to indicator circuit 18.

[0059] Still referencing Figure 1 If integrated circuit U1 detects a ground fault (as described above), relay synchronous switch 31 establishes a circuit path between power supply 13 for U1 VCC and rectifier SCR1 to turn off transistors Q1 and Q4.

[0060] While automatically testing the sensing circuit, the self-test circuit 33 isolates the ground fault sensing circuit (e.g., transformer T1, integrated circuit U1, and rectifier SCR1) from normal ground fault sensing operation. The self-test circuit 33 generates a short current pulse on test line 55 via transformer T1, which integrated circuit U1 senses as a ground fault. Integrated circuit U1 generates an SCR trigger signal to the gate of SCR1. If the rising charge stored in the automatic monitoring end-of-life logic module 35 exceeds the forward conduction voltage of SCR1, SCR1 triggers to conduct. If there is a fault in the sensing coil of integrated circuit U1, rectifier SCR1, or transformer T1, SCR1 will not conduct and will release the rising charge stored in the automatic monitoring end-of-life logic module 35. The rising charge will increase to the turn-on voltage of the end-of-life switch 35A, which will turn off SOL1 and cut off the output power, as described above.

[0061] Please also refer to Figure 2 It shows a schematic diagram of GFCI circuit 11A in an alternative embodiment of the high-frequency interference immunity ground fault circuit interrupter, which has STEOL. Circuit 11A has Figure 1 The common circuits shown here need not be discussed further. However, it is also understandable that using only one sensing transformer eliminates improper high-frequency (e.g., greater than 60Hz) tripping caused by high-frequency crosstalk between the two sensing transformers used in a typical GFCI circuit.

[0062] Still referencing Figure 2 This illustrates a dual-relay circuit 10A. Circuit 10A includes directional overcurrent relays CR1 and CR2, and associated switches CR1A and CR2A. If the current through CR1 or CR2 exceeds a predetermined value, the relays will open the associated switches CR1A and CR2A, thereby disconnecting the power supply to the load. It should also be understood that an open neutral line on the input side of the GFCI circuit 11A will disable CR1A and CR2A, thus preventing line voltage from being applied to the output load.

[0063] Please also refer to Figure 3 It shows a schematic diagram of GFCI circuit 11B in an alternative embodiment of the high-frequency interference immunity ground fault circuit interrupter of this invention, which has selectable 120 / 240 volt operating voltage and STEOL. Circuit 11B has the features previously described in Figure 1 and Figure 2 The circuits discussed earlier do not need to be discussed here.

[0064] Still referencing Figure 3It shows the 120 / 240V switch 11B1. Switch 11B1 allows the GFCI circuit 11B to be used in 120V or 240V line-powered circuits. It should also be understood that opening the neutral line on the input side of the GFCI circuit 11B will disable CR1B and CR2B, which will prevent line voltage from being applied to the output load.

[0065] Also refer to Figure 4 It shows a schematic diagram of the GFCI circuit 11C in an alternative embodiment of the manually reset high-frequency anti-interference ground fault circuit interrupter of the present invention, which has STEOL.

[0066] Still referencing Figure 4 The GFCI circuit 11C includes components arranged as shown and discussed herein. The GFCI circuit 11C includes interlocking switches SW1A and SW2B, relay circuit 1011, power supply circuit 1311, fault detection circuit 2911 for detecting electrical faults, bistable electronic latch circuit 2311, and test circuit 2711. Figure 1 The image also shows a self-tested end-of-life (STEOL) circuit 2811. The STEOL circuit 2811 includes a relay synchronization switch 3111, an analog ground fault generator and neutral ground sensing circuit 3311, an automatic monitoring and end-of-life logic circuit 3511, and an end-of-life switch 3511A.

[0067] Switches SW1A and SW2B are interlocking manual switches, located on the phase and neutral lines respectively between the power supply and the load. Switches SW1A and SW2B can be positioned in either of two connection positions. In the first connection position (e.g., Figure 1 As shown), switches SW1A and SW2B are positioned to disconnect the input power supply from the load. In the second connection position (with... Figure 1 (In the opposite position shown), switches SW1A and SW2B are positioned such that the input power supply is connected to the load.

[0068] Relay circuit 1011 is used to selectively position switches SW1A and SW2B in a first connection position or a second connection position. Relay circuit 1011 includes solenoid SOL1. Solenoid SOL1 is connected to the circuit breaker contacts of switches SW1A and SW2B and is responsible for selectively controlling the connection position of switches SW1A and SW2B. Before power is supplied to GFCI circuit 11C, solenoid SOL1 positions switches SW1A and SW2B in... Figure 4The connection positions are shown. When current I (SOL1) is supplied to solenoid SOL1 via relay synchronous switch 3111 through power supply circuit 1311, there is insufficient current to latch switches SW1A and SW2B, therefore manual latching is required. Once manually latched, sufficient current I (SOL1) flows through solenoid SOL1 to hold switches SW1A and SW2B in the latched connection position. It should also be understood that an open neutral line on the input side of GFCI circuit 11C disables solenoid SOL1, thereby preventing line voltage from being applied to the output load.

[0069] Power supply circuit 1311 supplies power to GFCI circuit 11C. Power supply circuit 1311 includes rectifier diodes D9 and D2, voltage drop resistors R18 and R17, and capacitors C4, C5, and C12.

[0070] When switches SW1A and SW2B are in their second connected position, fault detection circuit 2911 detects ground faults and neutral grounding conditions in the conductive lines. Fault detection circuit 2911 includes: sensing transformer T1, coupling capacitor CA, noise suppression capacitor C1, feedback resistor R3, diodes D10 and D11, and ground fault interrupter integrated circuit GFCI IC.

[0071] Upon a ground fault or neutral grounding condition on the load side of the GFCI circuit 11C, the sensing transformer T1 senses the current difference between the phase line and the neutral line and induces a related output from its secondary winding. The coupling capacitor CA couples the AC signal from the secondary winding of transformer T1 to the GFCI integrated circuit. Capacitor C1 prevents the fault detection circuit 2911 from operating in response to line interference (such as electrical noise and low-level faults). Capacitor CA and resistor R3 together set a minimum fault current at which the fault detection circuit 2911 provides an output signal to the latch-up circuit 2311. It should be understood that using only one sensing transformer eliminates high-frequency (e.g., greater than 60Hz) improper tripping caused by high-frequency crosstalk between the two sensing transformers used in a typical GFCI circuit.

[0072] Upon detecting a ground fault or neutral grounding condition, the GFCI integrated circuit generates an output pulse at pin 5 to activate the latch-up circuit 2311. The activated latch-up circuit 2311, via a relay synchronous switch 3111, deactivates or de-energizes the solenoid SOL1 by removing the excitation current I (SOL1). The latch-up circuit 2311 includes an NPN transistor Q1 and a noise suppression capacitor C3. The noise suppression capacitor C3 prevents the transistor Q1 from conducting due to electrical noise when it is in a non-conductive state.

[0073] Test circuit 2711 provides a means of testing whether a GFCI circuit is functioning correctly. Test circuit 2711 includes a test switch of a conventional push-in design. When the test switch is pressed to energize test circuit 2711, resistor R1 provides a simulated fault current to transformer T1, similar to a ground fault condition.

[0074] STEOL circuit 2811 includes: a relay synchronization switch 3111, an analog ground fault generator and neutral ground sensing circuit 3311, an automatic monitoring and end-of-life logic circuit 3511, and an end-of-life switch 3511A.

[0075] The simulated ground fault generator (SGFG) 3311 includes the logic and means required to simulate a periodic ground fault. The SGFG generates a short on-state pulse on test line 3311B. The SGFG pulse is sensed as a ground fault by the fault detection circuit 2911. Upon detection of the simulated ground fault, the GFCI integrated circuit generates an output pulse on pin 5 to activate the latch-up circuit 2311 (Q1).

[0076] When SGFG 3311 generates a short on-state pulse to automatically monitor the ground fault detection circuit, the GFCI relay synchronization switch 3111 also senses the SGFG pulse. The relay synchronization switch 3111, as described above, includes logic and means to temporarily disable normal GFCI fault detection. The GFCI components under test include the sensing transformer T1, the GFCI integrated circuit, and the bistable electronic latch-up circuit 2311.

[0077] It should be understood that the current I (SOL1) through solenoid SOL1 is the VCC power supply for the GFCI integrated circuit. It should also be understood that the timing window or pulse period set by SGFG has a sufficiently short duration so that when solenoid SOL1 is temporarily turned off during the auto-monitoring EOL window, the collapsed SOL1 magnetic field maintains sufficient current flowing through SOL1 to hold switches SW1A and SW2B in their connected positions. It can also be further understood that during the auto-monitoring EOL window, the collapsed SOL1 magnetic field maintains sufficient power for the GFCI integrated circuit.

[0078] The automatic monitoring and end-of-life logic circuit 3511 determines the number of times Q1 fails to conduct during the continuous automatic monitoring EOL window. If Q1 fails to conduct for the predetermined number of times, the GFCI fault detection circuit is faulty, the end-of-life switch 3511A is activated, and SOL1 is de-energized.

[0079] The present invention described above is merely exemplary, and those skilled in the art can make various changes and modifications to it without departing from the spirit of the present invention. All such changes and modifications are intended to fall within the scope of the present invention as defined by the appended claims. For example, specific parts constituting the embodiments may be interchanged or combined to form more embodiments.

Claims

1. A high-frequency anti-interference grounding fault circuit interrupter, which has a life-end self-test function, is used to interrupt the current flowing through a pair of lines, wherein, One of the two lines extends between the phase input and phase output terminals, and the other line extends between the neutral input and neutral output terminals. The high-frequency anti-interference grounding fault circuit interrupter includes: High-frequency GFCI, wherein the high-frequency GFCI includes: A first switch has a first input terminal and a first contact terminal; The second switch has a second input terminal and a second contact terminal; At least one relay circuit is provided for controlling the first switch and / or the second switch, wherein each switch includes a first position that is not energized and a second position that is energized, and the first switch is connected between the phase line input terminal and the phase line output terminal, and the second switch is connected between the neutral line input terminal and the neutral line output terminal; A fault detection circuit is used to detect grounding faults at the output terminal of a phase line, wherein the fault detection circuit includes: A sensing transformer is used to sense a ground fault at the output of the phase line, and the fault detection circuit does not include a second sensing transformer; The first bistable electronic latch circuit is used to de-energize the relay circuit when a fault is detected; A test module, integrated with the high-frequency GFCI, comprising: A simulated ground fault generator is used to simulate ground faults. Automatic monitoring logic module; Relay synchronous switch; A life-end switch is used to disable the at least one relay circuit; and A power supply circuit is provided to power the test module, the first bistable electronic latch circuit, the fault detection circuit, and the relay circuit, wherein the power supply circuit is connected to the phase line input terminal.

2. The high-frequency anti-interference grounding fault circuit interrupter as described in claim 1, wherein, It also includes a boost circuit for initializing the at least one relay circuit, wherein the boost circuit includes a diode connected to a first position where the switch is not energized.

3. The high-frequency anti-interference grounding fault circuit interrupter as described in claim 1, wherein, The power supply circuit includes: A capacitor-powered power supply circuit connected to a relay circuit, wherein the capacitor-powered power supply circuit reduces heat buildup and increases the switching contact force between the first input terminal and the first contact terminal, and between the second input terminal and the second contact terminal.

4. The high-frequency anti-interference grounding fault circuit interrupter as described in claim 1, wherein, The first bistable electronic latch-up circuit includes a first thyristor rectifier, which is capable of operating in a conductive or non-conductive state.

5. The high-frequency anti-interference grounding fault circuit interrupter as described in claim 4, wherein, The fault detection circuit also includes a GFCI integrated circuit, which is coupled to the sensing transformer.

6. The high-frequency anti-interference grounding fault circuit interrupter as described in claim 5, wherein, The automatic monitoring logic module measures a predetermined number of faults in the GFCI circuit in response to a simulated ground fault signal to test the GFCI circuit, wherein the GFCI circuit under test includes: Sensing transformer; GFCI integrated circuit coupled to the sensing transformer; and A first bistable electronic latch circuit connected to a GFCI integrated circuit, wherein the relay synchronous switch is connected to the GFCI integrated circuit.

7. The high-frequency anti-interference grounding fault circuit interrupter as described in claim 6, wherein, The relay synchronization switch temporarily disables normal GFCI fault detection by synchronizing the relay circuit with the generated ground fault signal to keep the first and second switches in the energized second position.

8. The high-frequency anti-interference grounding fault circuit interrupter as described in claim 1, wherein, The life-end switch for disabling the relay circuit can operate in response to a signal from the automatic monitoring logic module to set the first switch and the second switch to a first position where they are not energized.

9. The high-frequency anti-interference grounding fault circuit interrupter as described in claim 1, wherein, It also includes a common neutral line, which is connected to the neutral line input terminal and the test module, the first bistable electronic latch circuit, the fault detection circuit, the relay circuit and the power supply circuit, and the neutral line input terminal open circuit condition puts the first switch and the second switch in the first position of being de-energized.

10. A GFCI circuit for interrupting current flowing through a pair of lines, wherein, One of the two lines extends between the phase input and the phase output, and the other line extends between the neutral input and the neutral output. The GFCI circuit includes: A test module for detecting end-of-life conditions, the test module comprising: A simulated ground fault generator is used to simulate ground fault signals. Automatic monitoring logic module; Relay synchronous switch; and Life-end switch, used to disable GFCI circuit; A common neutral line connected to the neutral input terminal, wherein an open circuit at the neutral input terminal causes the first and second switches to be in the de-energized position.

11. The GFCI circuit as described in claim 10, wherein, The test module includes logic and means for generating simulated ground fault signals to test GFCI circuits, wherein the GFCI circuit under test includes: A sensing transformer, wherein the GFCI circuit does not include a second sensing transformer; GFCI integrated circuit, which is coupled to one of the sensing transformers; and First bistable electronic latch circuit.

12. The GFCI circuit as described in claim 10, wherein, The GFCI circuit also includes a relay circuit for controlling the first switch and / or the second switch, wherein the relay synchronization switch synchronizes the relay circuit with the generated ground fault signal to keep the relay circuit in the energized position during the generation of the ground fault signal.

13. The GFCI circuit as described in claim 10, wherein, The GFCI circuit also includes a relay circuit for controlling the first switch and / or the second switch, wherein the life-end switch is operable in response to a signal from the automatic monitoring logic module to return the relay circuit to the power-off position.

14. A high-frequency anti-interference grounding fault circuit interrupter, which has a life-end self-test function, is used to interrupt the current flowing through a pair of lines, wherein, One of the two lines extends between the phase input and phase output terminals, and the other line extends between the neutral input and neutral output terminals. The high-frequency anti-interference grounding fault circuit interrupter includes: GFCI, wherein the GFCI includes: A first switch has a first input terminal and a first contact terminal; The second switch has a second input terminal and a second contact terminal; At least one relay circuit is provided for controlling a first switch and / or a second switch, wherein each switch includes a first position that is not energized and a second position that is energized, wherein the first switch is connected between a phase line input terminal and a phase line output terminal, and the second switch is connected between a neutral line input terminal and a neutral line output terminal, wherein the relay circuit includes at least one directional overcurrent relay; A fault detection circuit is used to detect grounding faults at the output terminal of a phase line, wherein the fault detection circuit includes: A sensing transformer is used to sense a ground fault at the output terminal of a phase line, wherein the fault detection circuit does not include a second sensing transformer; The first bistable electronic latch circuit is used to de-energize the relay circuit when a ground fault is detected; A test module, which is integrated with the GFCI, includes: A simulated ground fault generator is used to simulate ground faults. Automatic monitoring logic module; Relay synchronous switch; A life-end switch is used to disable the at least one relay circuit; and A power supply circuit is provided to power the test module, the first bistable electronic latch circuit, the fault detection circuit, and the relay circuit, wherein the power supply circuit is connected to the phase line input terminal.

15. The high-frequency anti-interference grounding fault circuit interrupter as described in claim 14, wherein, It also includes a common neutral line, which is connected to the neutral line input terminal and the test module, the first bistable electronic latch circuit, the fault detection circuit, the relay circuit and the power supply circuit, wherein the neutral line input terminal is open-circuited, which puts the first switch and the second switch in the first position where they are not energized.

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