35kV Transmission Line Ground Fault Detection and Analysis Device

Abstract

Specifically, the box lid 100 and the box body 200 are made of engineering plastics. The box lid 100 and the box body 200 made of engineering plastics have high structural strength, light quality, and are convenient to carry. Above, the basic principle, main features and advantages of this utility model have been shown and explained. Those skilled in the art should understand that this utility model is not limited by the above embodiments, and what is described in the above embodiments and the specification is only to explain the principle of this utility model. Without departing from the spirit and scope of this utility model, there are various changes and improvements to this utility model, and all these changes and improvements should be understood to fall within the scope of this utility model that requires protection. The scope of this utility model registration is defined by the appended claims and their equivalents. This utility model discloses a grounding fault detection and analysis device for a 35 kV transmission line, mainly applied to the technical field of power grid fault detection equipment, including a box lid 100, a box body 200, and an industrial computer. The box lid 100 and the box body 200 are hinged. The control module 300 is installed inside the box body 20 0. The control module 300 includes an industrial computer, a touch screen 30 1, a high-voltage power output interface 302, a test connection line interface 303, an instrument grounding wire interface 304, a buzzer 305, a charging port 306, a switch 307, a soft start circuit, a reference voltage source, an error amplifier, a PWM / PFM switching control circuit, and on both sides of the touch display 30 1, there are a high-voltage power output interface 302, a test connection line interface 303, an instrument grounding wire interface 304, a buzzer 305, a charging port 306, a switch 307, an industrial computer, a touch display 301, a high-voltage power output interface 302, a test connection line Line interface 303, equipment ground wire interface 304, buzzer 305, charging port 30 6. The switch 307 is electrically connected to a soft start circuit, a reference voltage source, an error amplifier, and a PWM / PFM switching control circuit. The grounding fault detection and analysis device for the 35 kV transmission line of this utility model is applied, with a small volume, light maintenance quality, convenient to carry, convenient to operate, and can perform piecemeal insulation measurement on the positioned fault line, with high working efficiency. has a small volume, light maintenance quality, is convenient to carry, convenient to operate, and can perform piecemeal insulation measurement on the positioned fault line, with high working efficiency. can perform piecemeal insulation measurement on the positioned fault line, with high working efficiency.

Description

Technical Field

[0001] This utility model relates to the technical field of power grid fault detection equipment, specifically to a grounding fault detection and analysis device for 35kV transmission lines.

Background Art

[0002] People's dependence on domestic electricity in their lives is increasing, and the reliability of power supply to the power grid is also increasing. In recent years, the construction of the power grid has been developing rapidly, but the network structures of local power departments are weak and still cannot catch up with the development of power demand. The main problems in the current operation of transmission lines are as follows. 1. The search for faults in transmission lines is slow and it is difficult to locate faults. 2. The quality of inspection work is poor and the efficiency is not high. 3. Some power supply bureau jurisdictions have many mountains, and the terrain of the 35kV line area in mountainous areas is complex with thick trees, and fault location devices are not installed to cover them, resulting in frequent line faults. After a fault occurs, the investigation is difficult, and a lot of human and material resources are consumed. After a fault occurs, only fault investigation by manual line patrol can be carried out, and there is no specialized fault investigation device.

[0003] This utility model proposes a grounding fault detection and analysis device for 35kV transmission lines, solving the problems of difficult fault detection, low efficiency, poor quality, inconvenient portability, and relatively poor economy. The technical solution of this utility model is: a 35kV transmission line grounding fault detection and analysis device, including a box cover 100, a box body 200, and an industrial computer. The box cover 100 and the box 300 is an industrial computer, a touch screen 301, a high-voltage power supply output interface 30 2, a test connection line interface 303, an instrument ground wire interface 304, a buzzer 305 , a charging port 306, a switch 307, a soft start circuit, a reference voltage source, an error amplifier, PW M / PFM switching control circuit is installed, and high-voltage power supply output interfaces are on both sides of the touch display 301 tace 302, a test connection line interface 303, an instrument ground wire interface 304 , a buzzer 305, a charging port 306, a switch 307, an industrial computer, a touch display ray 301, a high-voltage power supply output interface 302, a test connection line interface 303, machine ground wire interface 304, a buzzer 305, a charging port 306, a switch 307 are electrically connected to a soft start circuit, a reference voltage source, an error amplifier, a PWM / PFM switching control circuit and are connected. Preferably, the box lid 100 and the box body 200 are made of engineering plastics. The technical problem that this utility model must solve is: to provide a grounding fault detection and analysis device for a 35kV transmission line. When in use, after checking that the state of the instrument is normal, connect it to the test line. After checking that there is no mistake in the wiring , check whether there is residual voltage on the test line through the touch display 301. If the residual voltage displayed on the interface is zero, the inspection operation can be performed , and the soft start circuit, the reference voltage source, the error amplifier, and the PWM / PFM switching control circuit cooperate in division of labor to diagnose the line fault. The beneficial effect of this utility model: The grounding fault detection and analysis device for a 35kV transmission line is small in volume, light in maintenance quality, convenient to carry, convenient to operate, can remotely measure the partial insulation of the positioned fault line , and has high working efficiency.

Brief Description of the Drawings

[0004]

Figure 1

Figure 2

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Embodiments for Carrying out the Invention

[0005] Specific embodiments of this utility model are, as shown in FIGS. 1 and 2, a 35 kV transmission line ground fault detection The output analysis device includes a box cover 100, a box body 200, and an industrial computer. The box cover 100 and the box body 2 00 are hinged. The control module 300 is installed inside the box body 200. The control module 300 is connected to an industrial computer, a touch screen 301, a high - voltage power output interface 302, a test connection line interface 303, an equipment ground wire interface 304, a buzzer 305, a charging port 306, a switch 307, a soft start circuit a reference voltage source, an error amplifier, and a PWM / PFM switching control circuit are installed. On both sides of the touch - type display 301 are a high - voltage power output interface 302, a test connection line interface 303 an equipment ground wire interface 304, a buzzer 305, a charging port 306, a switch 307, and an industrial Industrial computer, touch display 301, high-voltage power output interface 302, test connection line interface 303, equipment ground wire interface 304, buzzer 305, charging port 306, switch 307 are electrically connected to a soft start circuit, a reference voltage source, an error amplifier, a PWM / P FM switching control circuit. Soft start circuit: During the circuit startup phase, surge current and overshoot voltage are likely to occur. The output voltage is gradually increased to the preset voltage through the soft start circuit to protect the safe operation of the components. When the boost-type DC-DC converter starts the power-on operation, the output voltage gradually rises from zero to the predetermined value. Therefore, during the startup phase, the feedback voltage VFB is relatively small. When inputting it to the error amplifier together with the fixed reference voltage, the output of the error amplifier will be too high. Finally, the PWM comparator outputs a modulation signal with a large duty ratio, and the conduction time of the NMOS power tube is too long, the inductance current continues to increase, and the generated surge current and overshoot voltage damage the chip. To avoid such a situation, the soft start circuit of this utility model limits the output of the error amplifier so that the duty ratio signal does not become excessive with the gradually increasing reference voltage Vref_FB. Reference voltage source: It provides a high-precision reference voltage that is not affected by voltage source and temperature, and is realized by adopting a consumption-free structure. The reference voltage source with a consumption-free structure does not require a startup circuit, but the circuit structure is simpler, and the extremely low static power consumption meets the design goal of a high-efficiency system. To achieve high efficiency at full load for the boost-type DC-DC converter designed in this utility model, it is necessary to select a circuit structure with as low power consumption as possible. The conventional bandgap reference circuit does not meet this requirement. Therefore, a reference voltage source with a consumption-free structure is used to meet the design requirements of a high-efficiency system. The structure is complex, and it is necessary to use an operational amplifier circuit and a startup circuit. The performance of the operation directly affects the output reference voltage accuracy, and the quiescent current is generally a dozen or so μA, which is disadvantageous for high-efficiency design. This utility model adopts a depletion reference, simplifies the circuit structure, eliminates the need for an op-amp circuit and a startup circuit, reduces the layout area, saves costs, and can significantly reduce the static power consumption. Switching tubes M7, M8, and reinforcing tube M9. The signal EN is an enable control signal, and EN_N is its inverted control signal. When EN is at a high level, the circuit operates normally and in this case, the M1 tube is in the off state, and the M6 and M10 tubes are in the on state. M4, M5, and M11 consume power, but their threshold voltages are negative values. The gate of the M5 tube is directly connected, and when the M6 tube turns on, the gate-source voltage VGS5 becomes zero, generating a certain branch current . The consumption suppresses the channel length modulation effect despite the presence of M4, and can reduce the influence of VDD changes on the M5 tube current. The current in a certain branch of the M5 tube is copied to a certain branch of M9 through a current mirror, and is converted into the gate voltage of M9, that is, the reference voltage Vref through I-V. M12 is a switching tube and is controlled by the soft start signal V soft, and the reference voltage Vref_FB that gradually rises. Error amplifier: It is one of the core modules of the DC-DC converter of this utility model, and the quality of its performance directly affects the accuracy of the output voltage and the response speed of the system. The multi-stage amplifier has a high gain but a large quiescent current, which is also disadvantageous for compensation. For the DC-DC converter of this utility model, a single-stage amplifier better meets the low-power consumption design requirements, and adopting a folded cascode structure has a large gain and can meet the performance requirements of the chip. Different from the conventional folded cascode structure, the NMOS load of this utility model adopts a low-voltage connection method, and the output voltage amplitude of the error amplifier is larger. VBP1, VBP2, VBN 3, VBN4 provide appropriate bias voltages. The input terminals of the error amplifier are Vre f_FB and VFB respectively. The signal Vref_FB is supplied from the reference voltage circuit, and the signal VFB is the feedback voltage, which samples the output voltage value in real time at a specific ratio. V E is the output signal of the error amplifier, which is the differential amplification signal of Vref_FB and VFB. When the output voltage decreases, the VFB signal follows the decrease, Vref_FB > VFB, and the output signal VE rises , the duty ratio increases, and the recovery of the output voltage is adjusted. When the output voltage rises, the VFB signal follows the rise, Vref_FB < VFB, the output signal VE decreases, and the duty ratio decreases slightly to adjust the decrease of the output voltage. PWM / PFM switching control circuit: This utility model detects the duty ratio of the output signal VPWM of the PWM comparator. When increasing the load current from a light load, the duty ratio of the VPWM signal increases, and when it becomes large to a certain extent, it automatically switches to the PWM operation mode. Comparing the "hard" switching of the detection current, the detected duty ratio can make the switching between the PWM and PFM modes smoother . By comparing the high-level time of the output signal of the PWM comparator with the time required for the inductance current to reach the current limit value Ipfm, the signal with a longer duration determines the on-time of the NMOS power tube, making the switching of the system between the two operation modes of PWM and PFM smoother. PWM / PFM switching control circuit: A triangular wave signal VRAMP and the output signal VE of the error amplifier are respectively input to both ends of the PWM comparator, and the surge When the protection state ends, the surge protection circuit output signal Vrush becomes low level. The output signal VPWM of the PWM comparator is the switching control signal of the oscillator. When in the hop cycle state, the VPWM signal becomes low level throughout one cycle. At this time, the oscillator stops operating, reduces energy loss until the VPWM signal becomes high level again, and then the oscillator resumes operation. In one cycle, let the high level time of the output VPWM of the PWM comparator be t1, and the time when the inductor current reaches the current limiting point Ipfm be t2. During light load, the converter operates in the PFM mode, t1 < t2, the signal VPWM turns on the NMOS power tube. After reaching the peak current limiting point Ipfm, the Vipfm signal turns off the NMOS power tube and turns on the PMOS power tube to enter the continuous stage. The designed PWM / PFM switching control circuit in this article uses an RS flip-flop as the key logic circuit, and its specific operating principle is as follows: During light load, the output of the error amplifier is low, the output high level time of the VPWM signal is short, the S terminal of the input RS flip-flop, the initial state of the Vipfm signal is low level, the Q terminal holds high level, and NOR1 outputs a low level signal. OSC_N is the inversion of the oscillator signal OSC, which is low level at this time. The output signal control_N of NOR2 is high level, and at this time the NMOS power tube is turned on. Until the inductor current reaches the current limiting point Ipfm, the Vipfm signal becomes high level, the RS flip-flop is reset, the Q terminal becomes low level, at which time VPWM has already become low level, and control_N is low level, and at this time the NMOS power tube is turned off. When the load increases, the output signal VE of the error amplifier increases, and the high level time t1 of VPWM In one cycle, let the high level time of the output VPWM of the PWM comparator be t1, and the time when the inductor current reaches the current limiting point Ipfm be t2. During light load, the converter operates in the PFM mode, t1 < t2, the signal VPWM turns on the NMOS power tube. After reaching the peak current limiting point Ipfm, the Vipfm signal turns off the NMOS power tube and turns on the PMOS power tube to enter the continuous stage. The designed PWM / PFM switching control circuit in this article uses an RS flip-flop as the key logic circuit, and its specific operating principle is as follows: During light load, the output of the error amplifier is low, the output high level time of the VPWM signal is short, the S terminal of the input RS flip-flop, the initial state of the Vipfm signal is low level, the Q terminal holds high level, and NOR1 outputs a low level signal. OSC_N is the inversion of the oscillator signal OSC, which is low level at this time. The output signal control_N of NOR2 is high level, and at this time the NMOS power tube is turned on. Until the inductor current reaches the current limiting point Ipfm, the Vipfm signal becomes high level, the RS flip-flop is reset, the Q terminal becomes low level, at which time VPWM has already become low level, and control_N is low level, and at this time the NMOS power tube is turned off. When the load increases, the output signal VE of the error amplifier increases, and the high level time t1 of VPWM increases.​​​​​​ It increases. When t1 > t2, the on and off of the NMOS power tube are controlled by the VPWM signal and the OSC signal and are no longer affected by the Vipfm signal. That is, the converter enters the PWM operation mode. In this state, the specific operating principle of the PWM / PFM switching control circuit is as follows: The VPWM signal is input to the S terminal of the RS flip-flop. The Q terminal outputs a high level, and NOR1 outputs a low level. When the Vipfm signal becomes high level and Q becomes low level, the VPWM signal remains high level, NOR1 outputs a low level, and the NMOS power tube remains on until the PWM signal becomes low level.

Claims

1. A ground fault detection and analysis device for a 35 kV transmission line, including a box lid 100, a box body 200, and an industrial computer, The box lid 100 and the box body 200 are hinged, further including a control module 300, The control module 300 is installed inside the box body 200, The control module 300 includes an industrial computer, a touch display 301, a high-voltage power output interface 302, a test connection line interface 303, an equipment ground wire interface 304, a buzzer 305, a charging port 306, a switch 307, a soft start circuit, a reference voltage source, an error amplifier, and a PWM / PFM switching control circuit, On both sides of the touch panel 301, there are a high-voltage power output interface 302, a test connection line interface 303, an equipment ground wire interface 304, a buzzer 305, a charging port 306, a switch 307 are sequentially installed, The industrial computer, the touch display 301, the high-voltage power output interface 302, the test connection line interface 303, the equipment ground wire interface 304, the buzzer 305, the charging port 306, and the switch 307 are electrically connected to the soft start circuit, the reference voltage source, the error amplifier, and the PWM / PFM switching control circuit, A ground fault detection and analysis device for a 35 kV transmission line.

2. The ground fault detection and analysis device for a 35 kV transmission line according to Claim 1, The box lid 100 and the box body 200 are made of engineering plastic, A ground fault detection and analysis device for a 35 kV transmission line.

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