Lightning arrester resistive current calculation device based on BPC electric wave synchronization time

Abstract

The invention discloses a lightning arrester resistive current calculation device based on BPC electric wave synchronization time. The lightning arrester resistive current calculation device comprises a current sensor, a voltage sensor and a concentrator. The current sensor comprises an MCU module I, a power supply module I, a LoRa communication module I, a current acquisition module, a display module, an RTC module I and a BPC module I; the voltage sensor comprises an MCU module II, a power supply module II, a LoRa communication module II, a voltage acquisition module, an RTC module II and a BPC module II; the concentrator comprises an MCU module III, a power management module, a LoRa communication module III and a resistive current algorithm module; the current sensor and the voltage sensor carry out wireless data transmission through a LoRa communication network. According to the invention, wireless and real-time monitoring of the state of the lightning arrester is realized, on-site construction is facilitated, the cost is reduced, and the calculation precision of resistive current is improved, so that early warning can be carried out on the fault of the lightning arrester in time.

Description

Technical Field

[0001] The invention belongs to the technical field of state monitoring of power system equipment, and in particular relates to a lightning arrester resistive current calculation device based on BPC electric wave synchronization time. Background Art

[0002] With the popularity of zinc oxide lightning arresters in my country, a lot of scientific research has been carried out on the online monitoring and fault diagnosis technology of MOA lightning arresters in China, and fruitful results have been achieved. Effective monitoring methods have been summarized, including leakage current method, capacitive current compensation method, multi-component compensation method, third harmonic method, etc. Based on these methods, various types of lightning arrester online monitoring devices have been designed. The monitoring principles they adopt have different emphases and their performance also has advantages and disadvantages. The current lightning arrester resistive current calculation method and device are relatively mature in technology, and the transmission method mainly adopts bus or wired Ethernet. For example:

[0003] Chinese patent application No. 201911402839.7 discloses a live monitoring device for the operating characteristics of a zinc oxide lightning arrester, including a signal acquisition unit, a signal conditioning unit, a signal collection unit, and a network server; the signal acquisition unit is used to obtain a voltage signal from the bus, obtain a leakage current signal from the zinc oxide lightning arrester, and detect the external ambient temperature of the installation location of the zinc oxide lightning arrester to obtain a temperature signal; the signal conditioning unit is used to condition the voltage signal and the leakage current signal respectively; the signal collection unit is used to synchronously collect the conditioned voltage signal, leakage current signal and temperature signal; the network server is used to calculate the resistive current peak value of the zinc oxide lightning arrester, judge the resistive current peak value and obtain a judgment conclusion on whether the zinc oxide lightning arrester is faulty.

[0004] Chinese patent application No. 202110859767.X discloses a lightning arrester leakage current monitoring system, which includes: an interference current measuring device for detecting phase-to-phase interference current; a leakage full current measuring device for detecting the leakage full current of the lightning arrester; a voltage measuring device for detecting the phase voltage of the lightning arrester; a measuring device for obtaining the phase-to-phase interference current and the leakage full current of the lightning arrester; the leakage full current includes the current between the lightning arrester and the ground; the phase-to-phase interference current is removed from the leakage full current to obtain the leakage current; the voltage of the lightning arrester is obtained, and the phase angle is calculated based on the voltage and the leakage current; at least one of the resistive leakage current and the capacitive leakage current is obtained based on the leakage current and the phase angle.

[0005] Chinese patent application No. 202111155324.9 discloses a method for detecting zinc oxide lightning arresters powered on based on wireless synchronous current measurement technology, comprising the following steps: S1: Current synchronous acquisition modules are respectively arranged on the three-phase zinc oxide lightning arresters A, B, and C, and the current synchronous acquisition modules are connected in series between the counter and the arrester leakage current down conductor to collect leakage current; S2: The voltage synchronous acquisition module is connected in parallel to the PT secondary voltage to collect voltage; S3: The zinc oxide lightning arrester powered test host wirelessly sends a synchronous acquisition signal to the voltage synchronous acquisition module and the three current synchronous acquisition modules; S4: The voltage synchronous acquisition module and the three current synchronous acquisition modules collect the collected voltage and current data The data are summarized to the zinc oxide lightning arrester live test host for FFT calculation, and finally the full current, resistive current and angle test results are obtained; the current synchronization acquisition module includes a clamp-type current sensor, an AD chip, an ARM processor, a synchronization module, a wireless module, a power module, a lithium battery, a power acquisition module and an LCD display screen, the clamp-type current sensor is connected to the AD chip, the wireless module and the synchronization module are connected to the AD chip in sequence, the AD chip, the synchronization module, the wireless module, the power module, the LCD display screen are all connected to the ARM processor, the power module is connected to the lithium battery, and the lithium battery is connected to the ARM processor through the power acquisition module.

[0006] Chinese patent application No. 202211004425.0 discloses an online monitoring device for lightning arresters on power transmission and distribution lines, including a current signal detection unit, a voltage signal detection unit, a main control unit and a network remote control terminal; the current signal detection unit and the voltage signal detection unit respectively collect leakage current and bus voltage; the bus voltage and leakage current are transmitted to the main control unit for data processing and analysis, and the real-time resistive current value is calculated, and the waveforms of the bus voltage, leakage current and resistive current value are displayed in real time, and the bus voltage, leakage current and resistive current value are saved in real time to a database; the main control unit transmits the bus voltage, leakage current and resistive current value to the network remote control terminal; the patent realizes point-to-point data collection, and uploads the collected data to the database, and the client can retrieve, view and obtain data at any time.

[0007] Chinese patent application No. 202211461232.8 discloses a system for realizing an online monitoring method of leakage current of a lightning arrester in a transmission cable terminal field, including a cable main core current acquisition device, a cable sheath current acquisition device, a lightning arrester leakage current acquisition device, a current data monitoring module and a remote monitoring platform. The cable main core current acquisition device includes three cable main core current transformers respectively installed on the three-phase cable main core of phase A, phase B and phase C. The cable main core current transformer is used to collect the current signal I on the three-phase cable main core A ,IB ,I C The cable sheath current acquisition device includes three cable sheath current transformers installed on the three-phase cable sheath grounding wires of phase A, phase B, and phase C respectively. The cable sheath current transformer is used to collect the current signal I on the three-phase cable sheath a ,I b ,I c The arrester leakage current collection device includes three arrester leakage current transformers installed on the grounding system of the three-phase arrester of phase A, phase B and phase C respectively. The arrester leakage current transformer collects the leakage current I AT ,I BT ,I CT ; The current data monitoring module is used to obtain the current data collected by the cable main core current collection device, the cable sheath current collection device and the arrester leakage current collection device, and carry out data processing to analyze and warn of abnormal conditions of the arrester; The remote monitoring platform communicates with the current data monitoring module through the NB network, and is used to collect the current data uploaded by the current data monitoring module and review the abnormal conditions of the arrester.

[0008] Chinese patent application No. 202410157758.X discloses a lightning arrester resistive current measurement device, including: a current signal acquisition module, used to obtain a bus PT voltage signal, and collect the current signal of the lightning arrester according to the bus PT voltage signal; a lightning arrester digital signal determination module, used to determine the lightning arrester digital signal according to the current signal and a current-voltage converter; a fundamental current determination module, used to perform Fourier transform on the lightning arrester digital signal to obtain the fundamental current of the total current, and the amplitude and phase of the fundamental current; a phase resistive current determination module, used to determine the resistive current of each phase of the lightning arrester according to the amplitude and phase of the fundamental current, the phase angle difference between each phase current and the reference phase in the three-phase electricity, and the phase angle difference between the total current and each phase voltage.

[0009] With the rise of the Internet of Things and big data technologies in recent years, in-depth research on online detection technology of lightning arresters has found that the real-time performance, operation stability, sensor data collection accuracy, and automation level of lightning arrester monitoring systems can be further improved. Summary of the invention

[0010] The purpose of the present invention is to provide a lightning arrester resistive current calculation device based on BPC radio wave synchronization time. The present invention mainly uses current sensors and voltage sensors to respectively collect current signals and voltage signals in the power system, uses BPC radio wave signals for accurate time synchronization, ensures that current signals and voltage signals are collected at the same time, and transmits them to the concentrator through LoRa wireless, and realizes the calculation of lightning arrester resistive current on the concentrator. The present invention realizes wireless and real-time monitoring of lightning arrester status, facilitates on-site construction, reduces costs and improves the calculation accuracy of resistive current, so that lightning arrester failures can be warned in time.

[0011] In order to achieve the above object, the present invention adopts the following technical solutions:

[0012] A lightning arrester resistive current calculation device based on BPC radio wave synchronization time comprises a current sensor, a voltage sensor and a concentrator; the current sensor comprises an MCU module I and a power supply module I, a LoRa communication module I, a current acquisition module, a display module, an RTC module I and a BPC module I respectively connected to the MCU module I; the voltage sensor comprises an MCU module II and a power supply module II, a LoRa communication module II, a voltage acquisition module, an RTC module II and a BPC module II respectively connected to the MCU module II; the concentrator comprises an MCU module III and a power management module, a LoRa communication module III and a resistive current algorithm module respectively connected to the MCU module III; the current sensor and the voltage sensor respectively perform wireless data transmission through a LoRa communication network.

[0013] In the present invention, RTC module and BPC module are set in the current sensor and voltage sensor to ensure the synchronous collection of current data and voltage data, improve the calculation accuracy of the resistive current value of the arrester, and use the LoRa communication network for wireless data transmission to realize the wireless and convenient state monitoring of the arrester. MCU mainly collects the arrester leakage current data and voltage data collected at the same time, and then performs algorithm processing on the current data and voltage data collected at the same time to calculate the result of resistive current. The main purpose of the BPC module is to ensure that the current sensor and the voltage sensor are collected at the same time.

[0014] The RTC module is a single package module that integrates the RTC IC, oscillator circuit and main clock. There is no need to design the oscillator circuit and adjust the frequency by yourself. The core function of the RTC module is to provide accurate time information, including year, month, day, hour, minute, second, etc. It can run independently in the case of power failure, and as long as the backup power supply of the chip is always supplied, the time will keep running. The RTC module is essentially a timer that can still run after power failure, with the function of timing and triggering interrupts.

[0015] BPC module, namely China Code Radio Clock Module. The main function of China Code Radio Clock Module is to receive the timing signals transmitted by Shangqiu BPC Time Station and decode these signals through the built-in micro radio receiving system, so as to automatically adjust the timing of radio clocks and watches to keep them highly synchronized with the standard time. Its working principle includes: (1) Signal reception: The radio clock module receives the 68.5KHz OOK modulated signal transmitted by Shangqiu BPC Time Station through the built-in micro radio receiving system. These signals are transmitted via radio waves and have a wide coverage range, and can be received in most parts of China. (2) Signal decoding: The received signal is modulated by the built-in dedicated integrated chip to extract the time signal. The decoding process includes reading the pulse width, usually reading the output signal of the radio clock module once every 1 millisecond to ensure the accuracy of the decoding. (3) Time synchronization: The decoded time information is processed by the microcontroller, which automatically adjusts the timing device of the radio clock and watch to ensure that all radio clocks and watches receiving the standard time signal display strictly consistent time.

[0016] The present invention further illustrates that, in the current sensor, the RTC module I preferably adopts a PCF8563DTR module for time recording and synchronization, and for generating a timing acquisition interrupt signal and a timing upload signal; the BPC module I preferably adopts a MAS6180B chip development and design, which is responsible for receiving a BPC radio wave signal, which is a continuous binary code, parsing the binary code to obtain accurate time information, and then outputting a BPC synchronization signal to the MCU module I.

[0017] The present invention further illustrates that, in the current sensor, the power supply module I is used to supply power to each module of the current sensor; the MCU module I determines the sampling time according to the sampling period set by the concentrator, and then uses the time of BPC radio wave signal analysis as the synchronization signal to call the current acquisition module; the LoRa communication module I is responsible for transmitting the arrester leakage current data with timestamp to the concentrator through the LoRa wireless network; the current acquisition module is used to collect the leakage current of the arrester; the display module is used to display the arrester leakage current and the number of actions.

[0018] In the present invention, the power supply module I can preferably use a lithium-ion battery, and can also be connected to an external 24V power supply to provide electrical energy.

[0019] The present invention further illustrates that, in the voltage sensor, the RTC module II preferably adopts the PCF8563DTR module for time recording and synchronization, and for generating a timing acquisition interrupt signal and a timing upload signal; the BPC module II preferably adopts the MAS6180B chip development and design, which is responsible for receiving the BPC radio wave signal, which is a continuous binary code, parsing the binary code to obtain accurate time information, and outputting the BPC time synchronization signal to the MCU module II.

[0020] The present invention further illustrates that, in the voltage sensor, the power supply module II is used to supply power to each module of the voltage sensor; the MCU module II determines the sampling time according to the sampling period set by the concentrator, and then uses the time of BPC radio wave signal analysis as the synchronization signal to call the voltage acquisition module; the LoRa communication module II is responsible for transmitting the voltage data in the power grid where the lightning arrester is located with a timestamp to the concentrator through the LoRa wireless network; the voltage acquisition module is used to collect the voltage data in the power grid where the lightning arrester is located.

[0021] In the present invention, the power supply module II can preferably use a lithium-ion battery, and can also be connected to an external 24V power supply to provide electrical energy.

[0022] The present invention further illustrates that, in the concentrator, the power management module is used to supply power to each module of the concentrator; the LoRa communication module III is used to receive the arrester leakage current data and the voltage data in the power grid where the arrester is located, which are transmitted by the current sensor and the voltage sensor through the LoRa communication network; the resistive current algorithm module is used to match the voltage and current data with the timestamp of the collected data as the correlation condition, and use Fourier transform to extract the resistive component in the current; the MCU module III is responsible for reading the current data and voltage data received by the LoRa communication module III, and calling the resistive current algorithm module for calculation.

[0023] In the present invention, the power management module is externally connected to a 24V power supply to provide electrical energy.

[0024] The present invention further illustrates that the specific algorithm flow of the resistive current algorithm module includes the following steps:

[0025] (1) Decompose the voltage and current waveforms through Fourier transform to obtain the harmonic components and phases;

[0026] (2) Construct the resistive current expression through phase relationship and current harmonic components;

[0027] (3) Obtain the extreme points and calculate the effective value from the resistive current expression.

[0028] The present invention further illustrates that the resistive current expression includes:

[0029]

[0030] I Rn =I n cos(β n -α n )=I n [cos(β n )cos(α n )+sin(β n )sin(α n )],

[0031] In the above formula, U t is the voltage waveform, U 0 is the DC component, U n is the effective value of the nth harmonic voltage, ω=2πf, f=50Hz, t is the time, n is the harmonic number, I t is the current waveform, I 0 is the DC component of current, I n is the effective value of the nth harmonic current, I Rn is the nth resistive harmonic current value, α n is the subharmonic phase angle value of the voltage signal, β n is the subharmonic phase angle value of the current signal.

[0032] Advantages of the present invention:

[0033] 1. Convenient construction and reduced costs.

[0034] The present invention adopts BPC synchronous voltage sensor and current sensor, and transmits current and voltage data to the concentrator in real time through LoRa wireless transmission technology, thereby realizing accurate calculation of the resistive current of the lightning arrester, and realizing real-time and convenient monitoring process through wireless means, effectively reducing the complexity of on-site construction, reducing wiring and maintenance costs, and having higher economic benefits.

[0035] 2. Higher accuracy.

[0036] Compared with the traditional leakage current method, capacitive current compensation method, multi-component compensation method, third harmonic method, etc., this solution adopts the BPC radio wave-based synchronous acquisition of arrester current data and arrester voltage data, and uses the harmonic analysis algorithm to effectively improve the calculation accuracy of resistive current.

[0037] 3. Strong applicability.

[0038] The present invention has high applicability and can be widely used in state monitoring and evaluation of lightning arresters in power systems, thereby improving the intelligent level of operation and maintenance of lightning arresters. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 1 is a structural block diagram of a current sensor in one embodiment of the present invention.

[0040] Figure 2 1 is a structural block diagram of a voltage sensor in one embodiment of the present invention.

[0041] Figure 3 It is a structural block diagram of a concentrator in one embodiment of the present invention. DETAILED DESCRIPTION

[0042] The present invention is further described below in conjunction with the accompanying drawings.

[0043] Embodiment 1:

[0044] A lightning arrester resistive current calculation device based on BPC radio wave synchronization time comprises a current sensor, a voltage sensor and a concentrator; the current sensor and the voltage sensor respectively perform wireless data transmission through a LoRa communication network.

[0045] like Figure 1 As shown, the current sensor includes an MCU module I and a power supply module I, a LoRa communication module I, a current acquisition module, a display module, an RTC module I, and a BPC module I respectively connected to the MCU module I. Each module is further described as follows:

[0046] The RTC module I adopts PCF8563DTR module for time recording and synchronization, and for generating timing collection interrupt signal and timing sending signal.

[0047] The BPC module I is developed and designed using the MAS6180B chip, and is responsible for receiving the BPC radio wave signal, which is a continuous binary code. The binary code is parsed to obtain accurate time information, and then the BPC synchronization signal is output to the MCU module I.

[0048] The power supply module I is used to supply power to each module of the current sensor.

[0049] The MCU module I determines the sampling time according to the sampling period set by the concentrator, and then uses the time of BPC electric wave signal analysis as a synchronization signal to call the current acquisition module.

[0050] The LoRa communication module I is responsible for transmitting the arrester leakage current data with timestamp to the concentrator via the LoRa wireless network.

[0051] The current collection module is used to collect the leakage current of the lightning arrester.

[0052] The display module is used to display the leakage current and the number of actions of the arrester.

[0053] like Figure 2 As shown, the voltage sensor includes an MCU module II and a power supply module II, a LoRa communication module II, a voltage acquisition module, an RTC module II, and a BPC module II respectively connected to the MCU module II. Each module is further described as follows:

[0054] The RTC module II adopts the PCF8563DTR module for time recording and synchronization, and for generating a timing collection interrupt signal and a timing upload signal.

[0055] The BPC module II is developed and designed using the MAS6180B chip, and is responsible for receiving the BPC radio wave signal, which is a continuous binary code, parsing the binary code to obtain accurate time information, and outputting the BPC time synchronization signal to the MCU module II.

[0056] The power supply module II is used to supply power to each module of the voltage sensor.

[0057] The MCU module II determines the sampling time according to the sampling period set by the concentrator, and then uses the time of BPC electric wave signal analysis as a synchronization signal to call the voltage acquisition module.

[0058] The LoRa communication module II is responsible for transmitting the voltage data in the power grid where the lightning arrester is located with a timestamp to the concentrator through the LoRa wireless network.

[0059] The voltage acquisition module is used to collect voltage data in the power grid where the lightning arrester is located.

[0060] like Figure 3 As shown, the concentrator includes an MCU module III and a power management module, a LoRa communication module III, and a resistive current algorithm module respectively connected to the MCU module III. Each module is further described as follows:

[0061] The power management module is used to supply power to each module of the concentrator.

[0062] The LoRa communication module III is used to receive the arrester leakage current data and the voltage data in the power grid where the arrester is located, which are transmitted by the current sensor and the voltage sensor through the LoRa communication network.

[0063] The resistive current algorithm module is used to match the voltage and current data with the acquisition data timestamp as the correlation condition, and use Fourier transform to extract the resistive component in the current. By analyzing the harmonic components of the current, the resistive current and the capacitive current can be separated, among which the resistive current is a key indicator of the arrester status.

[0064] The MCU module III is responsible for reading the current data and voltage data received by the LoRa communication module III, and calling the resistive current algorithm module for calculation.

[0065] In this embodiment, the specific algorithm flow of the resistive current algorithm module includes the following steps:

[0066] (1) Decompose the voltage and current waveforms through Fourier transform to obtain the harmonic components and phases;

[0067] (2) Construct the resistive current expression through phase relationship and current harmonic components;

[0068] (3) Obtain the extreme points and calculate the effective value from the resistive current expression.

[0069] The resistive current expression includes:

[0070]

[0071] I Rn =I n cos(β n -α n )=I n [cos(β n )cos(α n )+sin(β n )sin(α n )],

[0072] In the above formula, U t is the voltage waveform, U 0 is the DC component, U n is the effective value of the nth harmonic voltage, ω=2πf, f=50Hz, t is the time, n is the harmonic coefficient, I t is the current waveform, I 0 is the DC component of current, I n is the effective value of the nth harmonic current, I Rn is the nth resistive harmonic current value, α n is the subharmonic phase angle value of the voltage signal, β n is the subharmonic phase angle value of the current signal.

[0073] This embodiment adopts the harmonic analysis method and the low-frequency time code (BPC) radio wave synchronization technology to achieve simultaneous acquisition of the arrester current waveform and voltage waveform, and uses the Internet of Things technology to achieve wireless transmission.

[0074] Obviously, the above embodiments are only examples for clearly explaining the present invention, and are not intended to limit the implementation of the present invention. For ordinary technicians in the relevant technical field, other different forms of changes or modifications can be made based on the above description; it is not necessary and impossible to list all the implementation methods here; and the obvious changes or modifications derived from them are still within the protection scope of the present invention.

Claims

1. A lightning arrester resistive current calculation device based on BPC radio wave synchronization time, characterized in that: It includes a current sensor, a voltage sensor and a concentrator; the current sensor includes an MCU module I and a power supply module I, a LoRa communication module I, a current acquisition module, a display module, an RTC module I, and a BPC module I respectively connected to the MCU module I; the voltage sensor includes an MCU module II and a power supply module II, a LoRa communication module II, a voltage acquisition module, an RTC module II, and a BPC module II respectively connected to the MCU module II; the concentrator includes an MCU module III and a power management module, a LoRa communication module III, and a resistive current algorithm module respectively connected to the MCU module III; the current sensor and the voltage sensor respectively perform wireless data transmission through the LoRa communication network.

2. The arrester resistive current calculation device based on BPC radio wave synchronization time according to claim 1 is characterized in that: In the current sensor, the RTC module I adopts the PCF8563DTR module for time recording and synchronization, and for generating timing collection interrupt signals and timing upload signals; the BPC module I is developed and designed using the MAS6180B chip, which is responsible for receiving the BPC radio wave signal, which is a continuous binary code. The binary code is parsed to obtain accurate time information, and then the BPC synchronization signal is output to the MCU module I.

3. The arrester resistive current calculation device based on BPC radio wave synchronization time according to claim 2 is characterized in that: In the current sensor, the power supply module I is used to supply power to each module of the current sensor; The MCU module I determines the sampling time according to the sampling period set by the concentrator, and then uses the time of BPC electric wave signal analysis as a synchronization signal to call the current acquisition module; The LoRa communication module I is responsible for transmitting the arrester leakage current data with timestamp to the concentrator through the LoRa wireless network; The current acquisition module is used to acquire the leakage current of the arrester; the display module is used to display the leakage current of the arrester and the number of actions.

4. The arrester resistive current calculation device based on BPC radio wave synchronization time according to claim 1 is characterized in that: In the voltage sensor, the RTC module II adopts the PCF8563DTR module for time recording and synchronization, as well as for generating timing collection interrupt signals and timing upload signals; the BPC module II is developed and designed using the MAS6180B chip, which is responsible for receiving the BPC radio wave signal, which is a continuous binary code. The binary code is parsed to obtain accurate time information, and the BPC time synchronization signal is output to the MCU module II.

5. The arrester resistive current calculation device based on BPC radio wave synchronization time according to claim 4 is characterized in that: In the voltage sensor, the power supply module II is used to supply power to each module of the voltage sensor; The MCU module II determines the sampling time according to the sampling period set by the concentrator, and then uses the time of BPC radio wave signal analysis as the synchronization signal to call the voltage acquisition module; the LoRa communication module II is responsible for transmitting the voltage data in the power grid where the lightning arrester is located with a timestamp to the concentrator through the LoRa wireless network; The voltage acquisition module is used to collect voltage data in the power grid where the lightning arrester is located.

6. The arrester resistive current calculation device based on BPC radio wave synchronization time according to claim 1, characterized in that: In the concentrator, the power management module is used to supply power to each module of the concentrator; the LoRa communication module III is used to receive the arrester leakage current data and the voltage data in the power grid where the arrester is located transmitted by the current sensor and the voltage sensor through the LoRa communication network; the resistive current algorithm module is used to match the voltage and current data with the timestamp of the collected data as the correlation condition, and use Fourier transform to extract the resistive component in the current; The MCU module III is responsible for reading the current data and voltage data received by the LoRa communication module III, and calling the resistive current algorithm module for calculation.

7. The arrester resistive current calculation device based on BPC radio wave synchronization time according to claim 6 is characterized in that: The specific algorithm flow of the resistive current algorithm module includes the following steps: (1) Decompose the voltage and current waveforms through Fourier transform to obtain the harmonic components and phases; (2) Construct the resistive current expression through phase relationship and current harmonic components; (3) Obtain the extreme points and calculate the effective value from the resistive current expression.

8. The arrester resistive current calculation device based on BPC radio wave synchronization time according to claim 7, characterized in that: The resistive current expression includes: I Rn =I n cos(β n -a n )=I n [cos(β n )cos(α n )+sin(β n )sin(a n )], In the above formula, U t is the voltage waveform, U0 is the DC component, U n is the effective value of the nth harmonic voltage, ω=2πf, f=50Hz, t is the time, n is the harmonic number, I t is the current waveform, I0 is the DC component of the current, I n is the effective value of the nth harmonic current, I Rn is the nth resistive harmonic current value, α n is the subharmonic phase angle value of the voltage signal, β n is the subharmonic phase angle value of the current signal.

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