Apparent Power Monitoring of Small Current and Real-time Disposal Platform

Abstract

The present invention discloses a platform for monitoring small current with apparent power and real-time disposal, belonging to the technical field of electromagnetic measurement. Its current sensor is used to detect the current on the line; the current sampling circuit in the apparent power sensor collects the detected current; the arithmetic unit multiplies the collected current by the given apparent voltage to obtain the apparent power, and accumulates the apparent power in real time to obtain the apparent electric quantity; the central processing unit reads the apparent electric quantity at set time intervals, calculates the change amount of the apparent electric quantity in each time period, compares the relative change amplitude of the change amounts of the apparent electric quantity in two adjacent time periods, and makes a decision to continue detection or report to the host; the host gives an alarm after receiving the alarm signal. This platform judges the change trend of the destructive energy in the line according to the change amplitude of the apparent electric quantity in adjacent time periods of the same length. When the growth amplitude of the apparent electric quantity is relatively large, it can give a warning signal to remind the staff to take safety inspection measures.

Description

Technical Field

[0001] The present invention belongs to the technical field of electromagnetic measurement, and particularly relates to a platform for monitoring small current with apparent power and real-time disposal. Background Art

[0002] Since the late 1960s in China, in order to strengthen the safety of electricity use, protective measures have been gradually adopted in the power system, and the leakage protector is a common technical means. The leakage protector detects abnormal current or voltage signals of the monitored equipment or line. When the detected signal reaches its set threshold, it prompts the actuator to cut off the power supply, avoiding accidents such as burning out electrical appliances, fires or electric shocks, so as to ensure the safety of personnel and electrical equipment and achieve the purpose of protection.

[0003] Later, some also adopted the method of small current grounding. An zero-sequence current transformer is installed at the incoming line end of the high-voltage equipment (i.e., the outgoing side of the high-voltage switch), and the secondary side of the current transformer is connected to the small current grounding line selection device. When one-phase grounding or two-phase grounding occurs in the high-voltage equipment loop, an unbalanced current will be generated in this loop. The current transformer detects the unbalanced current and transmits it to the small current grounding line selection device. The small current grounding line selection device gives a tripping signal to make the high-voltage switch trip, disconnecting the high-voltage equipment from the power grid, avoiding the high-voltage equipment from being burned, and at the same time avoiding expanding the fault range through the power grid.

[0004] The above protection measures all belong to the category of post-protection. Only when the defective current develops to a certain extent and reaches the protection threshold will they act. It is a method of starting protection only through power outage, and it cannot detect the development process of the destructive energy, and cannot prevent its development by early preventive treatment without affecting safety, or even eliminate the hidden dangers in the budding state. And once the protection threshold is reached, sudden power outage will occur, which will have a serious impact on production and life, especially for equipment involving people, such as elevators, transportation and entertainment equipment. With the rising construction of the ubiquitous power Internet of Things, safety, cleanliness, reduction of power outages, especially sudden power outages, have become an inevitable trend in the development of the power grid. At the same time, higher requirements are put forward for transparent power grids, fault prediction and power supply quality. This requires perceiving the working process of the entire distribution network, discovering hidden dangers through intelligent detection, facilitating timely disposal, achieving orderly power outages, reducing the number of power outages, shortening the power outage time, or even not having power outages at critical moments.

[0005] It can be seen that technologies such as leakage protectors and small current grounding can no longer meet the development needs of the power Internet of Things. There is an urgent need to develop a new detection technology that can actively discover problems to avoid disorderly power outages, and achieve the purpose of safe and energy-saving production and reduction of waste. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a platform for monitoring small current with apparent power and real-time disposal, which can automatically judge the change trend of current in the line according to the change amplitude of apparent power in adjacent same-length time periods, and give an early warning signal when the growth amplitude of apparent power is large, reminding the staff to take safety inspection measures.

[0007] To solve the above technical problem, the technical solution of the present invention is: design a platform for monitoring small current with apparent power and real-time disposal as needed, either simultaneously or separately, including a current sensor, and characterized by: an apparent power sensor, a central processor, and a host;

[0008] Current sensor: used to detect the current on the grounding wire, the grounding lead of the insulating part, or the zero-sequence current line, and obtain the current on the corresponding line;

[0009] Apparent power sensor: a current sampling circuit and an arithmetic unit are provided,

[0010] The current sampling circuit collects the detected current of the current sensor;

[0011] The arithmetic unit multiplies the current collected by the current sampling circuit by the given apparent voltage to obtain the apparent power, and accumulates the apparent power in real time to obtain the apparent power consumption;

[0012] Central processor: reads the apparent power consumption of the apparent power sensor at a set time interval, calculates the change amount of the apparent power consumption in each time period, compares the relative change amplitude of the change amounts of the apparent power consumption in two adjacent time periods, and makes a decision to continue detection or report to the host based on the relative change amplitude,

[0013] Electronic switching switches are provided on each acquisition port of the central processor;

[0014] Host: used to give an alarm after receiving the alarm signal from the central processor;

[0015] Used to send a pulse constant to verify the central processor or the apparent power sensor, and the host controls the central processor to be in the reading mode or the verification mode through the electronic switching switch.

[0016] 2. The platform for monitoring small current with apparent power and real-time disposal according to claim 1, characterized in that the processing process of the central processor for the apparent power consumption is as follows:

[0017] S1: Read the apparent power consumption once every interval time T. The reading time points divide the detection time into multiple time periods. The previous time period in two adjacent time periods is called the xth time period, and the latter time period is called the (x + 1)th time period, where x is a natural number;

[0018] S2: Read the apparent power consumption z in S3 at the starting point of the xth time periodx ;

[0019] S3: Read the apparent power in S3 at the end point of the x-th time period as z x+1 , and calculate the change amount of the apparent power in the x-th time period as: m x = z x+1 - z x ;

[0020] S4: Read the apparent power in S3 at the end point of the (x + 1)-th time period as z x+2 , and calculate the change amount of the apparent power in the (x + 1)-th time period as: m x+1 = z x+2 - z x+1 ;

[0021] Calculate the change amplitude n of the change amount of the apparent power in the (x + 1)-th time period relative to the change amount in the x-th time period x = m x+1 - m x , and judge n x relative to m x 's change amplitude;

[0022] S5: If n x ≤ 0.1m x , then x = x + 1, and repeat steps S4 and S5;

[0023] If 0.1m x < n x ≤ 0.3m x , then adjust the length of the time period to 1 / 5 - 1 / 10 T, restore x = 1, replace z x+2 with z x , and repeat steps S3 - 5;

[0024] If n x > 0.3m x , then report the information of n x , m x and m x+1 to the host computer.

[0025] Preferably, the central processing unit also sets a limit value K for the change amount of the apparent power in S4. If m x+1 ≤ K, then calculate n x and then enter S5; if m x+1 > K, then report m x , m x+1 to the host computer.

[0026] Preferably, the central processing unit further adds a step of detecting humidity between S4 and S5: detecting the humidity information s on the line, with the humidity set value being Q. If s > Q, the length of the time period is adjusted to 1 / 5 to 1 / 10 T; if s ≤ Q, the original time period length T is maintained.

[0027] Preferably, in step S5, if n x > 0.3 m x , the humidity information of the environment where the line is located is detected. If s x+1 > s x , the length of the time period is adjusted to 1 / 5 to 1 / 10 T, x = 1 is restored, and z x+2 is used to replace z x , and steps S6 to 8 are repeated; if s x+1 ≤ s x , then the information of n x , m x+1 and m x+2 is reported to the host.

[0028] Preferably, the central processing unit further adds a step of detecting temperature rise between detecting humidity and S5: detecting the temperature rise information f on the line, with the temperature rise set value being P. If f > P, the length of the time period is adjusted to 1 / 5 to 1 / 10 T; if f ≤ P, the original time period length T is maintained.

[0029] Preferably, the central processing unit also sets the number of stored change amplitudes n to Y, where Y is a natural number. When x + 1 > Y, n, m, and z each cover one digit forward, and then steps S4 and S5 are repeated.

[0030] Preferably, the host is also responsible for overall verification of the functions of the central processing unit. The host sends a verification instruction to switch the electronic switch to the host side, and the host issues a pulse constant; then a call measurement instruction is issued to read the values of all the acquisition ports of the central processing unit, and the first calculated value is obtained by cumulative calculation; the product of the pulse constant and the number of ports is calculated as the second calculated value; if the first calculated value is equal to the second calculated value, the overall reading of the central processing unit is correct; if the first calculated value is not equal to the second calculated value, there is an error in the overall reading of the central processing unit.

[0031] Preferably, the host is also responsible for single - path verification functions. The host first issues a call measurement instruction to read the apparent power read by each acquisition port of the central processing unit and sum them to obtain the total apparent power value a, and records the apparent power c of the acquisition port to be measured; then a verification instruction is issued to switch the electronic switch of the acquisition port to be measured to the host side, and the host issues a pulse constant; then a call measurement instruction is issued again to read the apparent power of each acquisition port and sum them to obtain the total apparent power value b. If b = a - c + pulse constant, the measured acquisition port is measured correctly, otherwise there is an error.

[0032] Preferably, the host computer can also clear the data in the central processing unit.

[0033] Preferably, the given apparent voltage is a set numerical information or an analog signal given by a voltage supply circuit.

[0034] Preferably, the numerical range of the apparent voltage is 1 - 20V.

[0035] Preferably, the alarm mode is to pop up alarm information on the screen, send mobile phone messages or display the location of the alarm on an electronic map. Compared with the prior art, the beneficial effects of the present invention are:

[0036] 1. Since the current sampling circuit is used to collect the grounding, insulation or leakage current and then multiply it by the given apparent voltage to form the apparent power, and the apparent power is accumulated into the form of apparent electric quantity, the change amplitude within two adjacent time periods of the same length can be calculated, truly reflecting the change trend of the destructive energy in the line. Necessary safety inspection measures can be taken to control its development trend or completely eliminate the destructive energy, avoiding the sudden tripping and power-off caused by the current reaching the threshold value in the prior art, thus laying a power foundation for ensuring normal production.

[0037] 2. This detection platform can overcome the drawbacks of unstable grounding, insulation or leakage current that is prone to misjudgment, or the current is too small to be detected and there are potential hazards; at the same time, it realizes the accumulation effect, avoiding the untrue reflection caused by instantaneous determination and increasing the number of times of unnecessary sudden power-off; in addition, it can also master the development trend of the destructive energy through the change amount of the apparent electric quantity, so as to take disposal measures such as system self-healing, online power-off, short-time power-off or planned power-off to ensure safe production, avoid waste of raw materials and reduce losses.

[0038] 3. Since the central processing unit takes into account the change factors such as humidity and temperature rise, it can judge whether the increase in the change amount of the apparent electric quantity within two adjacent time periods is caused by the increase in humidity or temperature rise, reducing the false alarm phenomenon; and after the humidity or temperature rise returns, it can judge whether the change in humidity or temperature rise has damaged the insulation performance of the line by whether the change amount drops.

[0039] 4. Since the central processing unit sets a limit value for the change amount of the apparent electric quantity, it can avoid the detection current slowly approaching the protection threshold value due to the small growth rate of the apparent electric quantity, making the detection more accurate on the premise of reducing the missed alarm phenomenon.

[0040] 5. Since the given apparent voltage, whether in the form of a set value or a voltage supply circuit, is an existing technology with mature technology, stable and reliable performance, and is easy to implement.

[0041] 6. Since the apparent voltage is estimated based on on-site conditions such as the grounding resistance and can be adjusted according to changes in on-site conditions, its value range is generally 1 - 20V. After adopting this apparent voltage, the detected micro-current can be converted into the form of apparent electric quantity reflecting the damage energy within a time period, truly reflecting the damage capabilities of the grounding current, insulation level, and leakage current to the power system.

[0042] 7. In the present invention, the apparent power sensor can be arranged on the grounding wire to detect the leakage current, or on the zero-sequence current line to detect the leakage current, or on the grounding lead of the equipment insulation part to detect its insulation level, and can be applied to high and low voltage AC and DC lines, with flexible and diverse application scenarios.

[0043] 8. The present invention breaks through the conventional protection methods and proposes a new method of active detection, monitoring the change process, and making timely and appropriate disposals. By means of the apparent electric quantity, the change trend of the damage energy is reflected, so as to take pre-event safety inspection measures, contain its development trend, and avoid sudden power outages, thus conforming to the construction of the ubiquitous power Internet of Things and facilitating popularization and application in this field. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 is the overall block diagram of the present invention;

[0045] Figure 2 is the schematic diagram of the time axis for the central processing unit to read the apparent electric quantity;

[0046] Figure 3 is the logical control block diagram of the central processing unit (upper part);

[0047] Figure 4 is Figure 3 the lower part of

[0048] Figure 5 is the working flow chart of the host;

[0049] Figure 6 is the logical block diagram for the host to perform overall verification on the central processing unit;

[0050] Figure 7 is the logical block diagram for the host to perform single-channel verification on the central processing unit (upper part);

[0051] Figure 8 is Figure 7 the lower part of DETAILED DESCRIPTION OF THE INVENTION

[0052] The present invention will be further described in detail below in conjunction with the drawings and the specific embodiments.

[0053] The main idea of the present invention is as follows: A current detection device is used to detect the current on the grounding wire of the device, the zero-sequence current line, or the grounding lead of the insulation part. After sampling the detected current, it is multiplied by a certain given apparent voltage to form apparent power. The apparent power is accumulated to obtain apparent electricity. Then, the apparent electricity is read once every time interval of the same duration. Check the change amount of the apparent electricity in the same time period. If the change amount of the apparent electricity in each time period does not change significantly and is basically in a stable state of being flat, it indicates that the destructive energy on the line has not changed significantly. Continue to maintain the above time interval to read the apparent electricity and check the change amount of the apparent electricity. If the change range of the apparent electricity reaches a certain level, then reduce the time interval for reading the apparent electricity, increase the reading frequency, and closely monitor the change of the apparent electricity in two adjacent same time periods. If there is no obvious increase, continue to maintain the monitoring state. If the apparent electricity drops back to the state before increasing the frequency, then adjust the time interval for reading the apparent electricity back to the original length. If the change range of the apparent electricity exceeds a certain value, immediately alarm or report to the host for alarm, notify the staff to take safety inspection measures in time, find out the reason for the change of the change amount of the apparent electricity, and take pre-treatment measures to contain the development trend of the increasing current, so as to avoid sudden tripping due to the current reaching the protection threshold in the prior art.

[0054] Of course, in the above process, a given value of the change amount of the apparent electricity can also be introduced. As long as the change amount reaches this given value, immediately alarm or report to the host for alarm to avoid the situation where although the increase range of the apparent electricity is not large relative to the change amount in the adjacent time, the accumulation in multiple time periods will also make the current in the detection circuit approach the protection threshold. Environmental change parameters such as humidity and temperature rise can also be introduced. When it is detected that the humidity or temperature rise reaches a certain value, similarly reduce the time interval for reading the apparent electricity, increase the reading frequency, and closely monitor the change of the apparent electricity in two adjacent same time periods. When the change range of the detected apparent electricity is relatively large, the change of humidity and temperature rise in two adjacent time periods can also be checked. If the humidity or temperature rise increases, it indicates that the increase range of the apparent electricity may be caused by the environment. Then, it can be monitored by increasing the reading frequency. If the humidity or temperature rise gradually drops back and the change amount of the apparent electricity also drops back, it indicates that the change of humidity and temperature rise does not damage the insulation performance of the device and there is no need to alarm, reducing the false alarm phenomenon of the system. If the humidity or temperature rise gradually drops back and the change amount of the apparent electricity does not drop back, it indicates that the change of humidity and temperature rise has damaged the insulation performance of the device to a certain extent, and it is necessary to alarm for safety inspection work and take pre-treatment measures to nip the defect in the bud.

[0055] To implement the above idea, as Figure 1 shown, in the specific early warning management platform adopted, a current sensor, an apparent power sensor, a central processor, and a host are set. Among them

[0056] Current sensor: It is used to detect the current on the grounding wire, the grounding lead of the insulating part or the zero-sequence current circuit, and serves as the current sampling device for the line;

[0057] The apparent power sensor is provided with a current sampling circuit and an arithmetic unit. The current sampling circuit collects the detected current of the current sensor, and then the arithmetic unit multiplies the detected current collected by the given apparent voltage to obtain the apparent power, and accumulates the apparent power in real time to obtain the apparent electricity quantity as the cumulative value;

[0058] The central processing unit reads the apparent electricity quantity of the apparent power sensor at the set time interval, calculates the change amount of the apparent electricity quantity in each time period, compares the relative change amplitude of the change amount of the apparent electricity quantity in two adjacent time periods, and makes a decision to continue detection or report to the host according to the relative change amplitude. As Figure 3 and Figure 4 shown, the processing process of its apparent electricity quantity is as follows:

[0059] S1: Read the apparent electricity quantity once every interval time T. The reading time points divide the detection time into multiple time periods. The previous time period in two adjacent time periods is called the xth time period, and the latter time period is called the (x + 1)th time period, where x is a natural number;

[0060] S2: Read the apparent electricity quantity in S3 as z at the starting point of the xth time period x ;

[0061] S3: Read the apparent electricity quantity in S3 as z at the end point of the xth time period x+1 , and calculate the change amount of the apparent electricity quantity in the xth time period as: m x = z x+1 -z x ;

[0062] S4: Read the apparent electricity quantity in S3 as z at the end point of the (x + 1)th time period x+2 , and calculate the change amount of the apparent electricity quantity in the (x + 1)th time period as: m x+1 = z x+2 -z x+1 ;

[0063] Calculate the change amplitude n of the change amount of the apparent electricity quantity in the (x + 1)th time period relative to the change amount in the xth time period x = m x+1 - m x , and judge the change amplitude of n x relative to m x ;

[0064] S5: If n x ≤0.1mx , then x = x + 1, and repeat steps S4 and S5;

[0065] If 0.1m x <n x ≤0.3 m x , then adjust the length of the time period to 1 / 5 - 1 / 10 T, and use z x+2 to replace z 1 , restore x = 1, and repeat steps S3 - 5;

[0066] If n x >0.3 m x , then report the information of n x , m x and m x+1 to the host to remind the staff to take security inspection measures.

[0067] To avoid the apparent power increasing at a small growth rate and causing the detection current to slowly approach the protection threshold, a limit value K of the change in apparent power is introduced, that is, m x+1 must be less than K for the above comparison. Once m x+1 is greater than K, it is also necessary to immediately report to the host. At the same time, considering reducing the influence of environmental changes, as long as the detected humidity exceeds the given value Q or the temperature rise exceeds the given value P, the time interval for reading the apparent power is adjusted to increase the reading frequency. When it is determined that n x >0.3m x , the consideration of humidity change is also introduced. If the average humidity in the latter time period is greater than the average humidity in the previous time period, it is considered that the change amplitude of the apparent power may increase due to the change in humidity. Therefore, instead of directly sending a host alarm, the reading frequency is increased and continuous close attention is paid; if the average humidity in the latter time period is not significantly greater than the average humidity in the previous time period, a host alarm will be sent, and the alarm methods are pop-up alarm information on the screen, sending mobile phone information, or displaying the alarm location on the electronic map.

[0068] To avoid storing a lot of data with little reference value due to the accumulation of data with a long reading time as the detection time extends, the number of change amplitudes n can be set to Y, where Y is a natural number and can be set to 5, 10, or 15 according to specific circumstances. It can be flexibly set, that is, only retain n 1 , n 2 , n 3 ……n Y and the related m values. When x + 1 > Y, use m 2 to replace m 1 , m 3 to replace m 2 , until m x+1 is used to replace mx , use z 2 to replace z 1 , z 3 to replace z 2 , until z x+2 to replace z x+1 , use n 2 to replace n 1 , n 3 to replace n 2 , until n x to replace n x-1 , such as Figure 2 shown, which is equivalent to n, m, and z each covering one digit forward respectively, and then calculating the new n x , continue to compare with m x ; if x + 1 ≤ Y, continue to detect until Y n values are saved.

[0069] To avoid the influence of the environment on data reading and be able to truly reflect the insulation performance of the device, considerations of humidity and temperature rise are also introduced. Set the humidity set value as Q and the temperature rise set value as P. Each time the apparent power is read, check the humidity value s and the temperature rise value f. If s > Q or f > P, the same as 0.1m x <n x ≤0.3m x In this case, adjust the length of the time period to 1 / 5 - 1 / 10 T, replace z x+2 with z 1 , restore x = 1, and repeat steps S3 - 5. Also when n x >0.3m x , check the value s of the humidity information in the next time period x+1 whether it is greater than s x , if s x+1 >s x , then do not report to the host temporarily, still take measures to adjust the length of the time period, adjust the length of the time period to 1 / 5 - 1 / 10 T, replace z x+2 with z 1 , restore x = 1, repeat steps S3 - 5 to closely monitor and determine that the change in the amplitude of the change has nothing to do with humidity and temperature rise. The humidity information used can be obtained by the maximum value analysis method, the average value method, the cumulative quantity analysis method, the humidity influence quantity analysis method, and the seasonal variable analysis method.

[0070] such as Figure 5As shown, the host is mainly used to read the data in the central processing unit, receive the alarm signal from the central processing unit, and alarm with the address information of the apparent power sensor attached to remind the staff to conduct security inspections in a timely manner. After the security inspection, the data in the central processing unit is cleared. At the same time, in order to ensure the accuracy of the central processing unit in reading the apparent power information, electronic switching switches are also set at each acquisition port of the central processing unit. The electronic switching switches can switch the acquisition port to the apparent power sensor or to the host. As Figure 6 shown, when calibration is required, set the number of acquisition ports of the central processing unit to be detected as E, and set the initial value of e to 1. Then the host issues a calibration instruction, and the electronic switching switch is connected to the line outputting the pulse constant by the host. The host issues the pulse constant, and each port of the central processing unit collects the pulse constant, reads the values of all the acquisition ports of the central processing unit, and accumulates and calculates to obtain the first calculated value; calculate the product of the pulse constant and the number of ports as the second calculated value; if the first calculated value is equal to the second calculated value, it indicates that the central processing unit is working properly; if the first calculated value is not equal to the second calculated value, it indicates that there is a problem with the central processing unit and it is working abnormally if they do not match.

[0071] As Figure 7 and Figure 8 shown, the host is also responsible for the single-channel calibration function. The host first issues a polling instruction to read the apparent power read by each acquisition port of the central processing unit and sum them to obtain the total apparent power value a, and record the apparent power c of the acquisition port to be tested; then issues a calibration instruction to switch the electronic switching switch of the acquisition port to be tested to the host side, and the host issues the pulse constant; then issues a polling instruction to read the apparent power of each acquisition port again and sum them to obtain the total apparent power value b. If b = a - c + pulse constant, it indicates that the apparent power sensor connected to this acquisition port is working properly, otherwise it is working abnormally. e = e + 1, determine whether e is greater than E. If it is greater, it indicates that all the acquisition ports have been detected; if it is not greater, switch to the next acquisition port and repeat the above process until all the acquisition ports have been detected, so as to respectively judge whether the apparent power sensors connected to each acquisition port of the central processing unit are normal.

[0072] The working process of the present invention is as follows:

[0073] The current sensor detects the current on the grounding wire, the grounding lead of the insulating part or the zero-sequence current line to obtain the current on the corresponding line. The current sampling circuit in the apparent power sensor collects the detected current, and then the arithmetic unit multiplies the current sampling by the given apparent voltage to obtain the apparent power; the obtained apparent power is accumulated in real time to obtain the apparent power consumption.

[0074] The central processing unit first detects the humidity value s and the temperature rise value f. If the humidity value s does not exceed its set value Q and the temperature rise value f does not exceed its set value P, then the apparent power is read once every time period length T; if either the humidity value s or the temperature rise value f exceeds its set value or both exceed their set values, then the reading interval time is adjusted to 1 / 5 - 1 / 10 T, and the apparent power read for the first time is z 1 Taking the first time period as the 1st period, the apparent power is read at the end point of the 1st time period as z 2 Calculate the change amount m of the apparent power within the 1st time period 1 = z 2 - z 1 The apparent power read at the end point of the 2nd period is z 3 Calculate the change amount m of the apparent power within the 2nd time period 2 = z 3 - z 2 , m 2 Relative to m 1 The change amplitude is n 1 =m 2 -m 1 If n 1 ≤0.1 m 1 Then the apparent power is read at the end point of the 3rd period as z 4 Calculate the change amount m of the apparent power within the 3rd time period 3 = z 4 - z 3 , m 3 Relative to m 2 The change amplitude is n 2 =m 3 -m 2 , n 2 ≤0.1 m 2 Then the apparent power is read at the end point of the 4th period as z 5 Read sequentially downwards until the Y + 2nd period is read, and n is calculated Y . Then the value of the latter point replaces the value of the former point, and the value of the latter period replaces the value of the former period. If the time axis extends to the right, it is equivalent to that every time the time T passes, the time axis moves one unit T to the left, and the coordinates on the time axis remain unchanged, and keep detecting. As Figure 2 shown, it is equivalent to that n, m, and z each cover one digit forward

[0075] During the above process, once 0.1m x <n x ≤0.3 m x , and the value range of x is 1 - Y, then the length of the time period is adjusted to 1 / 5 - 1 / 10 T, restore x = 1, and the zx+2 Instead of z x , start the detection again at the adjusted time period. Once n appears x > 0.3 m x , and if the humidity does not rise, then n x , m x and m x+1 The information of and m is reported to the host. After receiving the alarm information containing n x , m x and m x+1 , the host alarms in the form of text messages, pop-up screens, electronic maps or sound and light, so as to notify the staff to conduct security inspections according to the position where the power sensor is installed corresponding to the information. After the security inspection, the host clears the corresponding apparent power sensor through the central processing unit and conducts the detection again.

[0076] During the above entire detection process, the host can regularly issue calibration instructions for overall calibration or single-channel calibration. Since the pulse constant method is used for data acquisition calibration, the accumulated apparent power value needs to be output in the form of pulses. Of course, if the pulse calibration method is not considered, the apparent power sensor can completely give the apparent power value in the form of data.

[0077] In the above embodiment, the given value of the apparent voltage can be obtained by predicting through the method of multiplying the known grounding resistance by the measured current value, and adjusted according to the on-site situation. Its value range is generally 1 to 20V, and specifically can be any value within this range. The apparent voltage can be selected in the digital signal mode of the set value, or the analog signal mode of the voltage given circuit can be adopted. After adopting this apparent voltage, the detected micro current can be converted into the form of apparent power reflecting the damage energy within a time period, truly reflecting the damage ability of the grounding current, insulation level and leakage current to the power system; it also plays a corresponding amplification role in the detected current, improving the situation that the change is not obvious due to the very small detected current, improving the detection accuracy, and facilitating early adoption of security inspection measures.

[0078] The present invention can detect the grounding current on the grounding wire and the current on the grounding lead of the insulated part of the equipment; it can also detect the leakage current of the zero-sequence current line, that is, the differential current in the incoming and outgoing circuits, as well as in the AC and DC high- and low-voltage lines, and the application scenarios are flexible and diverse. It can comprehensively refer to the detection situation, on-site temperature, humidity, magnetic field and other influencing factors, truly reflect the damage energy on the line, and facilitate making accurate disposal measures.

[0079] The time interval for reading the apparent power can be flexibly set manually, and the specific length of the time period can be 1, 2, 3,..., up to 24 hours, and multiples of 10 of the above times.

[0080] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention in other forms. Any person skilled in the art may use the technical content disclosed above to make changes or modifications into equivalent embodiments with equivalent changes. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the technical solution content of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A platform for monitoring small current with apparent power and real-time disposal, including a current sensor, characterized in that: it further includes an apparent power sensor, a central processor and a host; Current sensor: used to detect the current on the grounding wire, the grounding lead of the insulating part or the zero-sequence current line, and obtain the current on the corresponding line; Apparent power sensor: provided with a current sampling circuit and an arithmetic unit, The current sampling circuit collects the detected current of the current sensor; The arithmetic unit multiplies the current collected by the current sampling circuit by the given apparent voltage to obtain the apparent power, and accumulates the apparent power in real time to obtain the apparent electricity; the given apparent voltage is the set numerical information or the analog signal given by the voltage given circuit; Central processor: reads the apparent electricity of the apparent power sensor at the set time interval, calculates the change amount of the apparent electricity in each time period, compares the relative change amplitude of the apparent electricity change amount in two adjacent time periods, and makes a decision to continue detection or report to the host based on the relative change amplitude, An electronic switch is provided on each acquisition port of the central processor; Host: used to give an alarm after receiving the alarm signal from the central processor; Used to send a pulse constant to verify the central processor or the apparent power sensor, and the host controls the central processor to be in the read operation or the verification operation through the electronic switch.

2. The platform for monitoring small current with apparent power and real-time disposal according to claim 1, characterized in that: The processing process of the central processor for the apparent electricity is as follows: S1: Read the apparent electricity once every interval time T. The reading time points divide the detection time into multiple time periods. The previous time period in two adjacent time periods is called the xth time period, and the latter time period is called the (x + 1)th time period, where x is a natural number; S2: Read the apparent power in S3 as z at the starting point of the x-th time period x ; S3: Read the apparent power in S3 at the end point of the x-th time period as z x+1 , and calculate the change in apparent power in the x-th time period as: m x = z x+1 -z x ; S4: Read the apparent power as z in S3 at the end point of the (x + 1)-th time period x+2 , and calculate the change in apparent power in the (x + 1)-th time period as: m x+1 = z x+2 - z x+1 ; Calculate the change amplitude n of the change amount of the apparent power in the (x + 1)-th time period relative to the change amount in the x-th time period x =m x+1 - m x , and judge n x relative to m x for its change amplitude; S5: If n x ≤ 0.1 m x , then x = x + 1, and repeat steps S4 and S5; If 0.1 m x <n x ≤0.3 m x , then the length of the adjustment time period is 1 / 5 to 1 / 10 T, restore x = 1, and use z x+2 to replace z x , and repeat steps S3 to S5; If n x > 0.3 m x , then report the information of n x , m x and m x+1 to the host computer.

3. The platform for monitoring small current with apparent power and real-time disposal according to claim 2, characterized in that: The central processing unit also sets a limit value K for the apparent power change amount in S4. If m x+1 ≤K, then calculate n x and enter S5; if m x+1 >K, then report m x , m x+1 to the host computer.

4. The platform for monitoring small current with apparent power and real-time disposal according to claim 3, characterized in that: The central processor also adds a step of detecting humidity between S4 and S5: detecting the humidity information s on the line, the humidity set value is Q. If s > Q, then adjust the length of the time period to 1 / 5 - 1 / 10 T; If s ≤ Q, then maintain the original time period length T.

5. The platform for monitoring small current with apparent power and real-time disposal according to claim 4, characterized in that: In step S5, if n x >0.3 m x When, detect the humidity information s of the environment where the circuit is located. If s x+1 >s x , then adjust the length of the time period to 1 / 5 - 1 / 10T, restore x = 1, and use z x+2 to replace z x , and repeat steps S6 - 8; if s x+1 ≤s x , then report the information of n x , m x+1 and m x+2 to the host. s x+1 is the humidity information of the next time period, and s x is the humidity information of the previous time period.

6. The platform for monitoring small current with apparent power and real-time disposal according to claim 4, characterized in that: When s ≤ Q in the step of detecting humidity, the central processor also adds a step of detecting temperature rise between detecting humidity and S5: detecting the temperature rise information f on the line, the temperature rise set value is P. If f > P, then adjust the length of the time period to 1 / 5 - 1 / 10 T; if f ≤ P, then maintain the original time period length T.

7. The platform for monitoring small current with apparent power and real-time disposal according to any one of claims 1 to 6, characterized in that: The central processor also sets the number of stored change amplitudes n to Y, Y is a natural number. When x + 1 > Y, n, m and z each cover one digit forward, and then repeat steps S4 and S5.

8. The apparent power monitoring small current and real-time disposal platform according to any one of claims 1 to 6, characterized in that: The host is also responsible for overall verification of the functions of the central processing unit. The host sends a verification instruction to switch the electronic switch to the host side, and the host issues a pulse constant; then it issues a polling instruction to read the values of all the acquisition ports of the central processing unit, and accumulates and calculates to obtain a first calculated value; Calculate the product of the pulse constant and the number of ports as the second calculated value; If the first calculated value is equal to the second calculated value, the overall reading of the central processing unit is correct; if the first calculated value is not equal to the second calculated value, there is an error in the overall reading of the central processing unit.

9. The apparent power monitoring small current and real-time disposal platform according to claim 8, characterized in that: The host is also responsible for single-channel verification function. The host first issues a polling instruction to read the apparent power of each acquisition port of the central processing unit and sum it to obtain the total apparent power value a, and records the apparent power c of the acquisition port to be measured; then it issues a verification instruction to switch the electronic switch of the acquisition port to be measured to the host side, and the host issues a pulse constant; then it issues a polling instruction to read the apparent power of each acquisition port again and sum it to obtain the total apparent power value b. If b = a - c + pulse constant, the measured acquisition port is measured correctly, otherwise there is an error.

10. The apparent power monitoring small current and real-time disposal platform according to claim 8, characterized in that: The host can also clear the data in the central processing unit.

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