A high-voltage line insulation resistance measurement method, measurement circuit and tester

Abstract

The present invention provides a method for measuring the insulation resistance of a high-voltage line, the steps of which include: using a high-voltage line insulation resistance measuring instrument to transmit a high-voltage pulse to the high-voltage line, if no loop is detected, the high-voltage line has insulation resistance; if a loop is detected and there is a time difference between the voltage signal and the current signal, the high-voltage line has insulation resistance; if a loop is detected and there is no time difference between the voltage signal and the current signal, the insulation resistance of the high-voltage line is damaged. The present invention also provides a high-voltage line insulation resistance measuring instrument, including a pulse transmitting device, a control module and a lithium battery pack; the pulse transmitting device transmits a high-voltage pulse to the high-voltage line, the control module determines whether there is a high-voltage metering device in the high-voltage line, and detects the insulation resistance parameters. The high-voltage line insulation resistance measuring instrument of the present invention can switch high-voltage pulses of different frequencies through a high-frequency current method to judge the insulation resistance on the loop line, and can accurately rule out the situation where a high-voltage meter exists on the high-voltage loop.

Description

Technical Field

[0001] The present invention relates to the field of high-voltage line maintenance, and in particular to a high-voltage line insulation resistance measurement method, a measurement circuit and a tester. Background Art

[0002] At present, when measuring high-voltage circuits, the insulation may decrease during operation, or even branches may hit the lines. In order to detect whether the insulation meets the safety regulations of the power grid, a high-voltage megohmmeter is often used to measure the insulation resistance on the high-voltage line, and whether the insulation meets the requirements is determined based on the size of the insulation resistance.

[0003] However, with the current deployment of smart grids, high-voltage meters such as CTs or PTs are often connected to high-voltage loop lines. These meters are essentially windings, with one end connected to the high-voltage line and the other to ground. This arrangement complies with installation regulations. However, when measuring insulation resistance, the current generated by the megohmmeter can flow through the windings and into the ground, resulting in a misjudgment of the insulation resistance. Summary of the Invention

[0004] To solve the above problems, the present invention provides a high-voltage line insulation resistance measurement circuit and a tester, and the technical solution is as follows:

[0005] A method for measuring the insulation resistance of a high-voltage line comprises the following steps: using a high-voltage line insulation resistance measuring instrument to transmit a high-voltage pulse to the high-voltage line; if no loop is detected, the high-voltage line has insulation resistance; if a loop is detected and there is a time difference between the voltage signal and the current signal, the high-voltage line has insulation resistance; if a loop is detected and there is no time difference between the voltage signal and the current signal, the insulation resistance of the high-voltage line is damaged.

[0006] A high-voltage line insulation resistance measuring instrument includes a pulse transmitter, a control module, and a lithium battery pack; the pulse transmitter transmits high-voltage pulses to the high-voltage line, the control module determines whether there is a high-voltage metering device on the high-voltage line, and detects insulation resistance parameters; the lithium battery pack provides energy for the pulse transmitter and the control module.

[0007] Furthermore, the pulse transmitting device has a transmitting frequency of 0 Hz to 10 Khz.

[0008] Furthermore, the pulse emission device includes a boost module, a current enable module and a safety module; the boost module converts the voltage of the lithium battery pack into high-voltage electrical energy; the current enable module generates a sequence of high-frequency currents; and the safety module protects the tester from the dangers of lightning and electric shock.

[0009] Furthermore, the control module includes an MCU computing unit and a high-frequency detection module. The MCU computing unit controls the pulse transmitting device. The high-frequency detection module detects and identifies the current fed back from the high-voltage line, determines whether the meter is grounded, and detects the insulation resistance.

[0010] Furthermore, the boost module adopts a push-pull structure and utilizes a small push-pull circuit to raise the battery voltage to high-voltage direct current energy.

[0011] Furthermore, the current enabling module includes a solid-state relay, one end of the solid-state relay is connected to the boost module, and the other end is connected to the high-frequency detection module via a high-voltage line.

[0012] Furthermore, the safety module includes a freewheeling diode D1, a current limiting resistor R1, a varistor R2 and a current sensor, which are electrically connected to each other, and the current sensor collects the current on the high-voltage line in real time.

[0013] A high-voltage line insulation resistance measurement circuit comprises a transformer, a high-voltage line, a high-voltage meter and the high-voltage line insulation resistance measuring instrument as described above; the transformer is connected to the high-voltage line, and one end of the high-voltage line insulation resistance measuring instrument is connected to the high-voltage line and the other end is connected to the ground.

[0014] Compared with the prior art, the beneficial effects are:

[0015] A high-voltage line insulation resistance measurement method of the present invention uses AC pulses to determine whether the insulation resistance of high-voltage wires is intact. By detecting the time difference between voltage signals and current signals, it can accurately eliminate the situation where other equipment in the high-voltage circuit affects the measurement conclusion.

[0016] The high-voltage line insulation resistance meter of the present invention uses a high-frequency current method to switch high-voltage pulses of different frequencies to determine the insulation resistance of the loop line, accurately eliminating the possibility of a high-voltage meter on the high-voltage loop. The high-voltage line insulation resistance meter can monitor the safety of the ground wire in real time, ensuring the safety of personnel and assisting frontline workers in quickly checking the safety of high-voltage lines, thereby improving work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1Schematic diagram of the principle of measuring the insulation resistance of high-voltage lines in the prior art a;

[0019] Figure 2 Schematic diagram b of the principle of measuring the insulation resistance of high-voltage lines in the prior art;

[0020] Figure 3 Schematic diagram c of the principle of measuring the insulation resistance of a high-voltage line in the prior art;

[0021] Figure 4 Schematic diagram a of the principle of a method for measuring insulation resistance of a high-voltage line according to the present invention;

[0022] Figure 5 Schematic diagram b of a high-voltage line insulation resistance measurement method of the present invention;

[0023] Figure 6 FIG3 is a schematic diagram c showing the principle of a method for measuring insulation resistance of a high-voltage line according to the present invention;

[0024] Figure 7 This invention provides a high-voltage line insulation resistance measurement circuit;

[0025] Figure 8 This is a structural schematic diagram of a high-voltage line insulation resistance measuring instrument of the present invention;

[0026] Figure 9 This is a schematic diagram of the working of a boost module of a high-voltage line insulation resistance measuring instrument of the present invention;

[0027] Figure 10 This is a working diagram of a current enabling module of a high-voltage line insulation resistance measuring instrument of the present invention;

[0028] Figure 11 The present invention is a schematic diagram of the working of a safety module of a high-voltage line insulation resistance measuring instrument. DETAILED DESCRIPTION

[0029] The embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

[0030] The following describes the embodiments of the present disclosure through specific examples, and those skilled in the art can easily understand other advantages and effects of the present disclosure from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all of the embodiments. The present disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present disclosure. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present disclosure.

[0031] A method for measuring the insulation resistance of a high-voltage line comprises the following steps: using a high-voltage line insulation resistance measuring instrument to transmit a high-voltage pulse to the high-voltage line. If no loop is detected, the high-voltage line has insulation resistance; if a loop is detected and there is a time difference between the voltage signal and the current signal, the high-voltage line has insulation resistance; if a loop is detected and there is no time difference between the voltage signal and the current signal, the high-voltage line's insulation resistance is damaged. The insulation resistance refers to the insulation layer of the high-voltage line. Damage to the insulation resistance refers to a breakdown of the insulation layer.

[0032] The existing technology measures the insulation resistance using a high voltage line insulation resistance meter, such as an AC power supply or an AC motor. Figure 1 As shown, the high-voltage line is not connected to other equipment and is not grounded. If the insulation resistance of the high-voltage line is intact, the measurement result is no loop.

[0033] like Figure 2 As shown, the high-voltage line is not connected to other equipment. If the insulation resistance of the high-voltage line is damaged, the measurement result will be that there is a loop.

[0034] like Figure 3 As shown, if the high-voltage line is connected to an inductive or capacitive device, such as a high-voltage meter such as a CT or PT, the measurement result will be that there is a loop regardless of whether the insulation resistance of the high-voltage line is intact.

[0035] Therefore, the existing DC measurement method cannot determine whether the insulation resistance is damaged.

[0036] This embodiment provides a method for measuring the insulation resistance of a high-voltage line. A high-voltage line insulation resistance measuring instrument transmits a high-voltage pulse to the high-voltage line. If a time difference is detected between the voltage and current signals in the loop, the high-voltage line has insulation resistance. If no time difference is detected between the voltage and current signals in the loop, the signals are returning through an inductive or capacitive device, indicating that the insulation resistance of the high-voltage line is damaged.

[0037] like Figure 4As shown, the high-voltage line is not connected to other equipment and is not grounded. If the insulation resistance of the high-voltage line is intact, the measurement result is no loop.

[0038] like Figure 5 As shown, the high-voltage line is not connected to other equipment. If the insulation resistance of the high-voltage line is damaged, the measurement result will be that there is a loop.

[0039] like Figure 6 As shown, if the high-voltage line is connected to an inductive or capacitive device, such as a high-voltage meter like a CT or PT, the test result will be a loop. If a time difference is detected between the current phase and the voltage phase, the high-voltage line insulation resistance is intact; otherwise, the high-voltage line insulation resistance is damaged.

[0040] like Figure 7 The figure shows a high-voltage line insulation resistance measurement circuit, including a transformer, a high-voltage line, a high-voltage meter, and a high-voltage line insulation resistance meter. The transformer is connected to the high-voltage line; one end of the high-voltage line insulation resistance meter is connected to the three phases of the high-voltage line and the other end is connected to the ground. The high-voltage meter is connected to the high-voltage line at one end and to the ground at the other end. The high-voltage line insulation resistance meter emits a series of high-voltage pulses with a frequency ranging from 0 Hz to 10 kHz. The control module uses an intelligent algorithm to determine whether a high-voltage metering device is present in the circuit and output insulation resistance parameters.

[0041] A high-voltage line insulation resistance measuring instrument includes a pulse transmitter, a control module, and a lithium battery pack. The pulse transmitter transmits high-voltage pulses to the high-voltage line, and the control module determines whether there is a high-voltage metering device on the high-voltage line and detects insulation resistance parameters. To better adapt to scenarios such as power outage maintenance, a high-capacity lithium battery pack is integrated inside the tester to provide energy for the pulse transmitter and the control module.

[0042] In this embodiment, the pulse transmitting device transmits at a frequency of 0 Hz to 10 Khz.

[0043] like Figure 8 As shown, the pulse transmitting device includes a boost module, a current enable module and a safety module; the boost module converts the voltage of the lithium battery pack into high-voltage electrical energy; the current enable module generates a series of high-frequency currents; and the safety module protects the tester from the dangers of lightning and electric shock.

[0044] like Figure 8-11 As shown, the control module includes an MCU computing unit and a high-frequency detection module, which are electrically connected. The MCU computing unit controls the pulse transmitter, while the high-frequency detection module detects and identifies the current fed back from the high-voltage line, determines whether the meter is grounded, and measures the insulation resistance.

[0045] like Figure 9As shown, the boost module adopts a push-pull structure, utilizing a small push-pull circuit to boost the battery voltage to high-voltage DC power. This power supply design employs a push-pull topology, converting the battery voltage to a DC voltage exceeding 300V. The battery voltage passes through windings Np1 and Np2, then flows through switches Q1 and Q2. The transformer secondary winding Ns receives power, which is then rectified by diodes to generate DC power. This DC power is sampled and fed back to the MCU's computing unit, where it is calculated and output as a PWM signal to switch Q1 and Q2 on and off, generating the desired voltage.

[0046] like Figure 10 As shown in the figure, the current enable module includes a solid-state relay. One end of the solid-state relay is connected to the boost module, and the other end is connected to the high-frequency detection module via a high-voltage line. The MCU calculation unit uses the enable terminal to continuously turn the solid-state relay on and off, achieving the purpose of generating a series of high-frequency currents.

[0047] like Figure 11 As shown, the safety module includes a freewheeling diode D1, a current-limiting resistor R1, a varistor R2, and a current sensor. The freewheeling diode D1, the current-limiting resistor R1, the varistor R2, and the current sensor are electrically connected. The current sensor collects the current on the high-voltage line in real time. If an overcurrent occurs, the MCU immediately shuts off the current enabling unit.

[0048] The present invention provides a high-voltage line insulation resistance measuring instrument that uses a high-frequency current method to switch between high-voltage pulses of varying frequencies to determine the insulation resistance of a loop line. This instrument can accurately exclude the presence of a high-voltage meter on a high-voltage loop and accurately identify the type of grounding method. The instrument can monitor ground wire safety in real time, ensuring worker safety and assisting frontline workers in quickly testing high-voltage line safety, thereby improving work efficiency.

[0049] In the present invention, unless otherwise expressly specified or limited, a first feature "on" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. "Multiple" means at least two, such as two or three, unless otherwise expressly specified or limited.

[0050] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0051] The above is only for explaining the embodiments of the present invention and is not intended to limit the present invention. For those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present invention without creative work should be included in the scope of protection of the present invention.

Claims

1. A method for measuring the insulation resistance of a high-voltage line, characterized in that the steps include: Connect the transformer to the high-voltage line, connect one end of the high-voltage line insulation resistance measuring instrument to the three phases of the high-voltage line and the other end to the ground, connect one end of the high-voltage meter to the high-voltage line and the other end to the ground, and the high-voltage line insulation resistance measuring instrument will send out a series of high-voltage pulses; use the high-voltage line insulation resistance measuring instrument to send high-voltage pulses to the high-voltage line. If no loop is detected, the high-voltage line has insulation resistance; if a loop is detected and there is a time difference between the voltage signal and the current signal, the high-voltage line has insulation resistance; if a loop is detected and there is no time difference between the voltage signal and the current signal, the insulation resistance of the high-voltage line is damaged.

2. A high-voltage line insulation resistance measuring instrument, used to implement the high-voltage line insulation resistance measuring method according to claim 1, characterized in that: The system comprises a pulse transmitter, a control module and a lithium battery pack; the pulse transmitter transmits high-voltage pulses to the high-voltage line, the control module determines whether there is a high-voltage metering device on the high-voltage line and detects insulation resistance parameters; the lithium battery pack provides energy for the pulse transmitter and the control module; The control module includes an MCU computing unit and a high-frequency detection module. The MCU computing unit controls the pulse transmitting device. The high-frequency detection module detects and identifies the current fed back from the high-voltage line, determines whether the meter is grounded, and detects the insulation resistance.

3. The high-voltage line insulation resistance measuring instrument according to claim 2, characterized in that: The pulse transmitting device has a transmitting frequency of 0 Hz to 10 Khz.

4. The high-voltage line insulation resistance measuring instrument according to claim 2, characterized in that: The pulse emission device includes a boost module, a current enable module and a safety module; the boost module converts the voltage of the lithium battery pack into high-voltage electrical energy; the current enable module generates a sequence of high-frequency currents; and the safety module protects the tester from the dangers of lightning and electric shock.

5. The high-voltage line insulation resistance measuring instrument according to claim 4, characterized in that: The boost module adopts a push-pull structure and utilizes a small push-pull circuit to raise the battery voltage to high-voltage direct current energy.

6. The high-voltage line insulation resistance measuring instrument according to claim 4, characterized in that: The current enabling module includes a solid-state relay, one end of the solid-state relay is connected to the boost module, and the other end is connected to the high-frequency detection module via a high-voltage line.

7. The high-voltage line insulation resistance measuring instrument according to claim 4, characterized in that: The safety module includes a freewheeling diode D1, a current limiting resistor R1, a varistor R2 and a current sensor. The freewheeling diode D1, the current limiting resistor R1, the varistor R2 and the current sensor are electrically connected, and the current sensor collects the current on the high-voltage line in real time.

8. A high voltage line insulation resistance measurement circuit, characterized in that: It includes a transformer, a high-voltage line, a high-voltage meter and a high-voltage line insulation resistance measuring instrument as described in any one of claims 2-7; the transformer is connected to the high-voltage line, and one end of the high-voltage line insulation resistance measuring instrument is connected to the high-voltage line and the other end is connected to the ground.

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