A measuring method for arc suppression coil grounding transformer imbalance tap adjustment

Abstract

The disclosure discloses a measurement method for arc suppression coil grounding transformer tap adjustment imbalance, comprising: measuring the neutral point voltage of the grounding transformer; measuring the three-phase capacitance value and the total ground capacitance value of the grounding transformer; inquiring the reactance value, the inductance value and the damping resistance value of the arc suppression coil; calculating the first displacement voltage at the tap adjustment place when the arc suppression coil is connected in series with the grounding transformer; calculating the second displacement voltage at the tap adjustment place when the arc suppression coil is connected in parallel with the grounding transformer; judging whether the tap of the grounding transformer meets the compensation range of the arc suppression coil when the arc suppression coil is connected in series with the grounding transformer according to the first displacement voltage; judging whether the tap of the grounding transformer meets the compensation range of the arc suppression coil when the arc suppression coil is connected in parallel with the grounding transformer according to the second displacement voltage.

Description

Technical Field

[0001] This disclosure pertains to the field of power distribution network testing, and specifically relates to a measurement method for adjusting the unbalanced tap of an arc suppression coil grounding transformer. Background Technology

[0002] When a single-phase ground fault occurs in a resonant grounding system, the arc suppression coil must be tuned quickly and accurately to compensate for the system's capacitive current, reduce the residual arc current at the fault point, and ensure the arc is extinguished rapidly and completely. Therefore, when the distribution network is operating normally, its capacitive current needs to be monitored and measured in real time to ensure the arc suppression coil can respond quickly during a fault. It can be seen that the accuracy of the arc suppression coil tuning is greatly affected by the accuracy of the system's capacitive current measurement. Currently, the methods used by various manufacturers to calculate the capacitive current in their arc suppression coil control devices mainly include the resonance method and the two-point method. Both methods primarily calculate the capacitive current by detecting changes in the neutral point voltage. Due to factors such as voltage sampling errors, grid fluctuations, and voltage drift in the arc suppression coil control device, to ensure relatively accurate calculation of the arc suppression coil's capacitive current, the arc suppression coil voltage is generally required to be greater than 30V (near the resonance point). The above two methods cannot verify the accuracy of the calculation results, resulting in poor reliability of the resonant capacitive current calculation results. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the purpose of this disclosure is to provide a measurement method and apparatus for adjusting the unbalanced tap of an arc suppression coil grounding transformer. This method and apparatus can improve the reliability of the capacitance current compensation calculation results when a single-phase grounding occurs in a resonant grounding system.

[0004] To achieve the above objectives, this disclosure provides the following technical solutions:

[0005] A measurement method for adjusting the unbalanced tap of an arc suppression coil grounding transformer includes the following steps:

[0006] S100: Measures the neutral point voltage of a grounding transformer;

[0007] S200: Measures the three-phase capacitance and total capacitance to ground of a grounding transformer;

[0008] S300: Query to obtain the reactance, inductance, and damping resistance values ​​of the arc suppression coil;

[0009] S400: Calculate the first displacement voltage at the tap adjustment point when the arc suppression coil is connected in series with the grounding transformer based on the neutral point voltage and three-phase capacitance value of the grounding transformer, as well as the damping resistance and inductance value of the arc suppression coil.

[0010] S500: Calculate the second displacement voltage at the tap adjustment point when the arc suppression coil is connected in parallel with the grounding transformer based on the neutral point voltage and total capacitance to ground of the grounding transformer, as well as the damping resistance and reactance of the arc suppression coil.

[0011] S600: Determine whether the tap of the grounding transformer meets the compensation range of the arc suppression coil when the arc suppression coil is connected in series with the grounding transformer based on the first displacement voltage.

[0012] S700: Determine whether the tap of the grounding transformer meets the compensation range of the arc suppression coil when the arc suppression coil is connected in parallel with the grounding transformer based on the second displacement voltage.

[0013] Preferably, in step S400, the first displacement voltage at the tap adjustment point when the arc suppression coil is connected in series with the grounding transformer is calculated by the following formula:

[0014]

[0015] in, C is the neutral point voltage of the system after the arc suppression coil is taken out of operation. a For the grounding capacitance of phase A of the grounding transformer, C b For the grounding capacitance of phase B of the grounding transformer, C c R is the C-phase grounding capacitance of the grounding transformer, R is the series damping resistance value of the arc suppression coil (obtained by consulting equipment parameters), j is the imaginary unit, w is the angular frequency, and L is the inductance value of the arc suppression coil.

[0016] Preferably, in step S500, the second displacement voltage at the tap adjustment point when the arc suppression coil is connected in parallel with the grounding transformer is calculated using the following formula:

[0017]

[0018] in, C is the neutral point voltage of the system after the arc suppression coil is taken out of operation. ∑ X is the total capacitance to ground of the grounding transformer, R is the parallel damping resistance of the arc suppression coil, and X is the total capacitance to ground of the grounding transformer. L ω represents the reactance of the arc suppression coil, j is the imaginary unit, w is the angular frequency, and * is the multiplication sign.

[0019] Preferably, step S600 includes the following steps:

[0020] S601: Adjust the setting of the arc suppression coil and measure the displacement voltage of the arc suppression coil at each setting. Find the resonance point of the arc suppression coil based on the variation law of the displacement voltage.

[0021] S602: Calculate the neutral point displacement voltage of the arc suppression coil based on the resonant point of the arc suppression coil;

[0022] S603: During the measurement of displacement voltage of the arc suppression coil at each position, if the neutral point displacement voltage of the arc suppression coil does not reach the maximum value when the arc suppression coil is lowered to the lowest position or raised to the highest position, it is determined that the tap of the grounding transformer meets the compensation range of the arc suppression coil.

[0023] Preferably, step S700 includes the following steps:

[0024] S701: Adjust the setting of the arc suppression coil and measure the displacement voltage of the arc suppression coil at each setting. Find the resonance point of the arc suppression coil based on the variation law of the displacement voltage.

[0025] S702: Calculate the neutral point displacement voltage of the arc suppression coil based on the resonant point of the arc suppression coil;

[0026] S703: During the measurement of displacement voltage of the arc suppression coil at each position, if the neutral point displacement voltage of the arc suppression coil does not reach the maximum value when the arc suppression coil is lowered to the lowest position or raised to the highest position, it is determined that the tap of the grounding transformer meets the compensation range of the arc suppression coil.

[0027] This disclosure also provides a measuring device for adjusting the unbalanced tap of an arc suppression coil grounding transformer, comprising:

[0028] The first measurement module is used to measure the neutral point voltage of the grounding transformer;

[0029] The second measurement module is used to measure the three-phase capacitance and total capacitance to ground of the grounding transformer.

[0030] The query module is used to query and obtain the reactance, inductance, and damping resistance values ​​of the arc suppression coil.

[0031] The first calculation module is used to calculate the first displacement voltage at the tap adjustment point when the arc suppression coil is connected in series with the grounding transformer, based on the neutral point voltage and three-phase capacitance value of the grounding transformer, as well as the damping resistance and inductance value of the arc suppression coil.

[0032] The second calculation module is used to calculate the second displacement voltage at the tap adjustment point when the arc suppression coil is connected in parallel with the grounding transformer, based on the neutral point voltage and total capacitance to ground of the grounding transformer, as well as the damping resistance and reactance of the arc suppression coil.

[0033] The first judgment module is used to determine whether the tap of the grounding transformer meets the compensation range of the arc suppression coil when the arc suppression coil is connected in series with the grounding transformer based on the first displacement voltage.

[0034] The second judgment module is used to determine whether the tap of the grounding transformer meets the compensation range of the arc suppression coil when the arc suppression coil and the grounding transformer are connected in parallel, based on the second displacement voltage.

[0035] Preferably, the first measurement module includes a voltage and current sampling board.

[0036] Preferably, the second measurement module includes a capacitance current tester.

[0037] Preferably, both the first computing module and the second computing module employ a CPU unit.

[0038] Preferably, both the first judgment module and the second judgment module employ a CPU unit.

[0039] Compared with the prior art, the beneficial effects of this disclosure are: it simplifies the need for on-site testing personnel to manually calculate the voltage for adjusting the unbalanced tap of the grounding transformer, overcomes the disadvantage of the difficulty in on-site debugging of the arc suppression coil, and protects the normal operation of the power grid. Attached Figure Description

[0040] Figure 1 This is a flowchart of a measurement method for adjusting the unbalanced tap of an arc suppression coil grounding transformer, provided in one embodiment of this disclosure;

[0041] Figure 2 This is a schematic diagram of a circuit structure in which an arc suppression coil and a grounding transformer are connected in series, according to another embodiment of this disclosure;

[0042] Figure 3 This is a schematic diagram of a circuit structure in which an arc suppression coil and a grounding transformer are connected in parallel, according to another embodiment of this disclosure. Detailed Implementation

[0043] The following will refer to the appendix. Figures 1 to 3 Specific embodiments of this disclosure are described in detail. While specific embodiments of this disclosure are shown in the accompanying drawings, it should be understood that this disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art.

[0044] It should be noted that certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. This specification and claims do not distinguish components based on differences in terminology, but rather on differences in function. The terms "comprising" or "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising but not limited to." The following descriptions are preferred embodiments for carrying out this disclosure; however, these descriptions are for the purpose of understanding the general principles of the specification and are not intended to limit the scope of this disclosure. The scope of protection of this disclosure is determined by the appended claims.

[0045] To facilitate understanding of the embodiments of this disclosure, further explanations and descriptions will be provided below with reference to the accompanying drawings and specific embodiments. The accompanying drawings do not constitute a limitation on the embodiments of this disclosure.

[0046] In one embodiment, such as Figure 1 As shown, this disclosure provides a measurement method for adjusting the unbalanced tap of an arc suppression coil grounding transformer, comprising the following steps:

[0047] S100: Measures the neutral point voltage of a grounding transformer;

[0048] S200: Measures the three-phase capacitance and total capacitance to ground of a grounding transformer;

[0049] S300: Query to obtain the reactance, inductance, and damping resistance values ​​of the arc suppression coil;

[0050] S400: Calculate the first displacement voltage at the tap adjustment point when the arc suppression coil is connected in series with the grounding transformer based on the neutral point voltage and three-phase capacitance value of the grounding transformer, as well as the damping resistance and inductance value of the arc suppression coil.

[0051] S500: Calculate the second displacement voltage at the tap adjustment point when the arc suppression coil is connected in parallel with the grounding transformer based on the neutral point voltage and total capacitance to ground of the grounding transformer, as well as the damping resistance and reactance of the arc suppression coil.

[0052] S600: Determine whether the tap of the grounding transformer meets the compensation range of the arc suppression coil when the arc suppression coil is connected in series with the grounding transformer based on the first displacement voltage.

[0053] S700: Determine whether the tap of the grounding transformer meets the compensation range of the arc suppression coil when the arc suppression coil is connected in parallel with the grounding transformer based on the second displacement voltage.

[0054] In another embodiment, such as Figure 2 As shown, when the arc suppression coil L and the grounding transformer are connected in series (i.e., one side of the arc suppression coil L is connected in series with the damping resistor R, and the other side is connected to the ground capacitances Ca, Cb, and Cc in sequence through the mains power supplies Ea, Eb, and Ec), the first displacement voltage at the tap adjustment point of the arc suppression coil and the grounding transformer is calculated using the following formula:

[0055]

[0056] in, C is the neutral point voltage of the system after the arc suppression coil is taken out of operation. a For the grounding capacitance of phase A of the grounding transformer, C b For the grounding capacitance of phase B of the grounding transformer, C cR is the C-phase grounding capacitance of the grounding transformer, R is the series damping resistance value of the arc suppression coil (obtained by consulting equipment parameters), j is the imaginary unit, w is the angular frequency, and L is the inductance value of the arc suppression coil.

[0057] In this embodiment, the calculation process of the above formula is as follows:

[0058] according to Figure 2 The circuit in the diagram lists the voltage balance equations, namely...

[0059]

[0060] After arranging both sides, we can obtain:

[0061]

[0062] make

[0063] X L =jwL

[0064] C ∑ =C a +C b +C c

[0065] We can obtain:

[0066]

[0067] In another embodiment, such as Figure 3 As shown, when the arc suppression coil L and the grounding transformer are connected in parallel (i.e., one side of the arc suppression coil L is connected in parallel with the damping resistor R, and the other side is connected to the ground capacitances Ca, Cb, and Cc in sequence through the mains power supplies Ea, Eb, and Ec), the second displacement voltage at the tap adjustment point of the arc suppression coil and the grounding transformer is calculated using the following formula:

[0068]

[0069] in, C is the neutral point voltage of the system after the arc suppression coil is taken out of operation. ∑ C is the total capacitance to ground of the grounding transformer. ∑ =C a +C b +C c R is the parallel damping resistance value of the arc suppression coil, X L ω represents the reactance of the arc suppression coil, j is the imaginary unit, and w is the angular frequency.

[0070] In another embodiment, step S600 includes the following steps:

[0071] S601: Adjust the setting of the arc suppression coil and measure the displacement voltage of the arc suppression coil at each setting. Find the resonance point of the arc suppression coil based on the variation law of the displacement voltage.

[0072] S602: Calculate the neutral point displacement voltage of the arc suppression coil based on the resonant point of the arc suppression coil and according to equation (1);

[0073] S603: During the measurement of displacement voltage of the arc suppression coil at each position, if the neutral point displacement voltage of the arc suppression coil does not reach the maximum value when the arc suppression coil is lowered to the lowest position or raised to the highest position, it is determined that the tap of the grounding transformer meets the compensation range of the arc suppression coil.

[0074] In another embodiment, step S700 includes:

[0075] S701: Adjust the setting of the arc suppression coil and measure the displacement voltage of the arc suppression coil at each setting. Find the resonance point of the arc suppression coil based on the variation law of the displacement voltage.

[0076] S702: Calculate the neutral point displacement voltage of the arc suppression coil based on the resonant point of the arc suppression coil and according to equation (2);

[0077] S703: During the measurement of displacement voltage of the arc suppression coil at each position, if the neutral point displacement voltage of the arc suppression coil does not reach the maximum value when the arc suppression coil is lowered to the lowest position or raised to the highest position, it is determined that the tap of the grounding transformer meets the compensation range of the arc suppression coil.

[0078] In another embodiment, this disclosure provides a measuring device for adjusting the unbalanced tap of an arc suppression coil grounding transformer, comprising:

[0079] The first measurement module is used to measure the neutral point voltage of the grounding transformer;

[0080] The second measurement module is used to measure the three-phase capacitance and total capacitance to ground of the grounding transformer.

[0081] The query module is used to query and obtain the reactance, inductance, and damping resistance values ​​of the arc suppression coil.

[0082] The first calculation module is used to calculate the first displacement voltage at the tap adjustment point when the arc suppression coil is connected in series with the grounding transformer, based on the neutral point voltage and three-phase capacitance value of the grounding transformer, as well as the damping resistance and inductance value of the arc suppression coil.

[0083] The second calculation module is used to calculate the second displacement voltage at the tap adjustment point when the arc suppression coil is connected in parallel with the grounding transformer, based on the neutral point voltage and total capacitance to ground of the grounding transformer, as well as the damping resistance and reactance of the arc suppression coil.

[0084] The first judgment module is used to determine whether the tap of the grounding transformer meets the compensation range of the arc suppression coil when the arc suppression coil is connected in series with the grounding transformer based on the first displacement voltage.

[0085] The second judgment module is used to determine whether the tap of the grounding transformer meets the compensation range of the arc suppression coil when the arc suppression coil and the grounding transformer are connected in parallel, based on the second displacement voltage.

[0086] In another embodiment, the first measurement module includes a voltage and current sampling board.

[0087] In this embodiment, the voltage and current sampling board uses the industrial-grade high-precision AD706 chip as the analog-to-digital converter for front-end acquisition. The AD sampling control chip is an FPGA chip. The FPGA is the Xilinx Artix-7 series XC7A50T. The Artix-7 series reduces power consumption by half and cost by 35%, adopts a miniaturized package and a unified Virtex series architecture, and can meet the performance requirements of the low-cost, high-volume market. It is commonly used in high-speed data acquisition and processing systems, communication systems, high-precision instruments, and high-end CNC systems.

[0088] In another embodiment, the second measurement module includes a capacitance current tester.

[0089] In another embodiment, the first calculation module, the second calculation module, the first judgment module, and the second judgment module all employ a CPU unit.

[0090] In this embodiment, the CPU unit uses an ARM+FPGA-based chip as the embedded core processor. The ARM processor is the NXP IMX6Q, which has a high processing speed and can run at a maximum clock speed of 1.2GHz. The IMX6Q also features three low-power control modes and integrates more peripheral interfaces on the chip. The main control chip runs Linux 4.15 as the overall system. A 10-inch 1280*800 TFT color touchscreen display is used as the human-machine interface.

[0091] In another embodiment, the device further includes a power management module.

[0092] In this embodiment, the power management module uses Linear Technology's LTM4644IY DC-DC converter, which can convert the 12V battery voltage to the +5V and +3.3V required by the control board. The power management module uses a PWM buck-mode 18650 battery charging management IC for independent lithium battery charging management, featuring trickle, constant current, and constant voltage charging modes, making it ideal for lithium battery charging management. In constant voltage charging mode, the battery voltage is modulated at 12.6V; in constant current charging mode, the charging current is set by an external resistor. When the input power supply's current output capability decreases, the internal circuitry can automatically shut down, eliminating the need for worst-case scenarios and maximizing battery output power protection, making it ideal for applications powered by handheld devices.

[0093] In another embodiment, the device further includes a communication module.

[0094] In this embodiment, the communication module adopts a WIFI communication module, and the WIFI module adopts an SDIO interface to facilitate communication and interconnection with smart devices.

[0095] The above-described specific implementations may be partially adjusted by those skilled in the art in different ways without departing from the principles and purpose of this disclosure. The scope of protection of this disclosure is determined by the claims and is not limited to the above-described specific implementations. All solutions within the scope of this disclosure are bound by this disclosure.

Claims

1. A method for measuring the tap adjustment of an arc suppression coil and a grounding transformer, comprising the following steps: S100: measuring the neutral point voltage of the grounding transformer; S200: measuring the three-phase capacitance value and the total ground capacitance value of the grounding transformer; S300: obtaining the reactance value, the inductance value and the damping resistance value of the arc suppression coil; S4 S400: calculating the first displacement voltage at the tap adjustment when the arc suppression coil is connected in series with the grounding transformer according to the neutral point voltage and the three-phase capacitance value of the grounding transformer and the damping resistance value and the inductance value of the arc suppression coil; S500: calculating the second displacement voltage at the tap adjustment when the arc suppression coil is connected in parallel with the grounding transformer according to the neutral point voltage and the total ground capacitance value of the grounding transformer and the damping resistance value and the reactance value of the arc suppression coil; S600: judging whether the tap of the grounding transformer meets the compensation range of the arc suppression coil when the arc suppression coil is connected in series with the grounding transformer according to the first displacement voltage; S700: judging whether the tap of the grounding transformer meets the compensation range of the arc suppression coil when the arc suppression coil is connected in parallel with the grounding transformer according to the second displacement voltage; wherein, the step S600 comprises the following steps: S601: adjusting the gear of the arc suppression coil, measuring the displacement voltage when the arc suppression coil is in each gear, and finding the resonance point of the arc suppression coil according to the change rule of the displacement voltage; S602: calculating the neutral point displacement voltage of the arc suppression coil based on the resonance point of the arc suppression coil; S603: in the process of measuring the displacement voltage when the arc suppression coil is in each gear, when the arc suppression coil is lowered to the lowest gear or raised to the highest gear, if the neutral point displacement voltage of the arc suppression coil does not reach the maximum value, it is judged that the tap of the grounding transformer meets the compensation range of the arc suppression coil; the step S700 comprises the following steps: S701: adjusting the gear of the arc suppression coil, measuring the displacement voltage when the arc suppression coil is in each gear, and finding the resonance point of the arc suppression coil according to the change rule of the displacement voltage; S702: calculating the neutral point displacement voltage of the arc suppression coil based on the resonance point of the arc suppression coil; S703: in the process of measuring the displacement voltage when the arc suppression coil is in each gear, when the arc suppression coil is lowered to the lowest gear or raised to the highest gear, if the neutral point displacement voltage of the arc suppression coil does not reach the maximum value, it is judged that the tap of the grounding transformer meets the compensation range of the arc suppression coil; The method can simplify the manual calculation of the voltage of the grounding transformer by the field test personnel, overcome the difficulty of on-site debugging of the arc suppression coil, and protect the normal operation of the power grid.

2. The method of claim 1, wherein, In the step S400, the first displacement voltage at the tap adjustment when the arc suppression coil is connected in series with the grounding transformer is calculated by the following formula: ； wherein, C is the system neutral point voltage after the arc suppression coil is out of operation, a C is the grounding transformer A phase grounding capacitance, b C is the grounding transformer B phase grounding capacitance, c C is the grounding transformer C phase grounding capacitance, R is the series damping resistance value of the arc suppression coil, which is obtained by querying the equipment parameters, and j is an imaginary unit, is the angular frequency, and L is the inductance value of the arc suppression coil.

3. The method of claim 1, wherein, In the step S500, the second displacement voltage at the tap adjustment when the arc suppression coil is connected in parallel with the grounding transformer is calculated by the following formula: ； wherein, V is the system neutral point voltage after the arc suppression coil is out of operation, C is the total capacitance of the grounding transformer to ground, R is the parallel damping resistance value of the arc suppression coil, X L X is the reactance value of the arc suppression coil, j is the imaginary unit, ω is the angular frequency, * is the multiplication symbol. 4.A device for measuring the tap adjustment of an arc suppression coil and a grounding transformer according to any one of claims 1 to 3, comprising: a first measuring module for measuring the neutral point voltage of the grounding transformer; a second measuring module for measuring the three-phase capacitance value and the total ground capacitance value of the grounding transformer; The query module is configured to query the reactance value, the inductance value and the damping resistance value of the arc-extinguishing coil. The first calculation module is configured to calculate a first displacement voltage at a tap adjustment position when the arc-extinguishing coil is connected in series with the grounding transformer according to the neutral point voltage of the grounding transformer, the three-phase capacitance value, the damping resistance value and the inductance value of the arc-extinguishing coil. The second calculation module is configured to calculate a second displacement voltage at the tap adjustment position when the arc-extinguishing coil is connected in parallel with the grounding transformer according to the neutral point voltage of the grounding transformer, the total capacitance value to ground, the damping resistance value and the reactance value of the arc-extinguishing coil. The first judgment module is configured to judge whether the tap of the grounding transformer satisfies the compensation range of the arc-extinguishing coil when the arc-extinguishing coil is connected in series with the grounding transformer according to the first displacement voltage. The second judgment module is configured to judge whether the tap of the grounding transformer satisfies the compensation range of the arc-extinguishing coil when the arc-extinguishing coil is connected in parallel with the grounding transformer according to the second displacement voltage.

5. The apparatus of claim 4, wherein, The first measurement module comprises a voltage and current sampling board.

6. The apparatus of claim 4, wherein, The second measurement module comprises a capacitance current tester.

7. The apparatus of claim 4, wherein, The first calculation module and the second calculation module both adopt a CPU unit.

8. The apparatus of claim 4, wherein, The first judgment module and the second judgment module both adopt a CPU unit.

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