CN116008755B - Method and system for detecting multipoint grounding of electrolytic tank based on voltage response of injection signal - Google Patents
Method and system for detecting multipoint grounding of electrolytic tank based on voltage response of injection signal Download PDFInfo
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Abstract
The invention discloses a multipoint grounding detection method and system for an electrolytic cell based on voltage response of an injection signal, wherein the method comprises the steps of loading alternating-current excitation voltage to an electrolytic cell group and synchronously measuring alternating-current voltage and direct-current voltage of each electrolytic cell when the electrolytic cell group has a grounding fault, calculating alternating-current of the electrolytic cell, and comparing alternating-current currents of adjacent electrolytic cells of each group: if the alternating current i m of any electrolytic cell #m is greater than a times the alternating current i m+1 of the electrolytic cell #m+1 adjacent to the electrolytic cell #m, the electrolytic cell #m is judged to have the ground fault, and all the electrolytic cells with the ground fault are finally determined, wherein a is greater than 1. The electrolytic tank capable of rapidly positioning the insulation faults caused by insulation degradation such as metal grounding faults, damp and the like has the advantages of simple and convenient detection and high positioning accuracy.
Description
Technical Field
The invention relates to the technical field of metal electrolysis, in particular to an electrolytic cell multipoint grounding detection method and system based on injection signal voltage response.
Background
The metal electrolytic bath including aluminum electrolytic bath is generally composed of bath body, anode and cathode, the anode chamber and cathode chamber are separated by diaphragm, and the electrolytic bath is divided into water solution electrolytic bath, molten salt electrolytic bath and non-water solution electrolytic bath according to the electrolyte, which is an important device for producing metal material. For example, china is a large country for producing aluminum, and aluminum yield is more than half of the world for a long time. However, the aluminum industry in China has a plurality of problems at present, such as over high energy consumption ratio, uneven yield distribution, large pollution and the like. The electrolytic tank mainly comprises an upper structure, a cathode structure, a bus structure and an electric insulation four part. Among them, whether the electrical insulation of the electrolyzer is good can greatly affect the yield and quality of aluminum, and also has a critical effect on safe production. Therefore, in industrial production, the electrolytic cell is provided with at least thirteen insulating parts, such as corresponding insulation parts at the positions of a cathode bus and a bus bar pier, a cell shell and a pillar, a bracket and a grid plate, a short circuit port and the like, so as to prevent various insulation faults. Among a plurality of fault types, the grounding fault of the electrolytic cell is one of more common types, and when the fault occurs, zero drift phenomenon often occurs, namely, a series of zero potential points drift to other places from the original midpoint, so that great hidden danger is brought to safe production, and meanwhile, the productivity and the production quality of an electrolytic aluminum enterprise are also negatively influenced. In addition, the ground fault often occurs simultaneously with multiple points, and each fault point forms a loop with a loop, for example, a loop is formed through a steel bar in a terrace, and a large current may cause ignition or personal safety accidents. Therefore, it is necessary to diagnose and locate the earth fault of the electrolytic cell in time and eliminate the earth fault.
Currently, there are many studies on the positioning of an earth fault of an electrolytic cell, and whether the earth fault occurs or not and the specific position of the fault point are determined by measuring various parameters of the cell or the cell to the earth. The positioning method for the grounding fault of the electrolytic cell with wider use comprises the following steps: an insulation resistance detection method, namely directly detecting the insulation resistance to the ground of the electrolytic cell by using a universal meter, so as to judge whether each cell has faults or not; the cell voltage detection method is to monitor the voltages at two ends of each electrolytic cell by using a PLC, and calculate and analyze the approximate position of a fault point; and the zero drift detection method is used for finding out the series zero positions after faults occur, so that the positions where the faults occur are obtained. However, the range of the grounding resistance which can be measured by the insulation resistance detection method is too small, and the measurement can not be performed in the face of the metallic grounding condition; both the tank voltage detection method and the zero drift detection method can accurately measure the single-point grounding fault position, but cannot accurately measure the multi-point grounding condition of two or more points.
Disclosure of Invention
The invention aims to solve the technical problems: aiming at the problems in the prior art, the invention provides a multipoint grounding detection method and a multipoint grounding detection system for an electrolytic cell based on injection signal voltage response.
In order to solve the technical problems, the invention adopts the following technical scheme:
An electrolytic cell multipoint grounding detection method based on injection signal voltage response, comprising: when the grounding fault of the electrolytic cell group is detected, alternating current excitation voltage is loaded to the electrolytic cell group, alternating current voltage and direct current voltage of each electrolytic cell are synchronously measured, alternating current of the electrolytic cell is calculated, and alternating current of adjacent electrolytic cells of each group is compared: if the alternating current i m of any electrolytic cell #m is greater than a times the alternating current i m+1 of the electrolytic cell #m+1 adjacent to the electrolytic cell #m, the electrolytic cell #m is judged to have the ground fault, and all the electrolytic cells with the ground fault are finally determined, wherein a is greater than 1.
Optionally, the function expression for calculating the alternating current of the electrolytic cell is:
im＝umIs/Um，
In the above formula, I m represents an ac current of any cell #m, U m represents an ac voltage of the cell #m, I s represents a dc current of the cell group, and U m represents a dc voltage of the cell #m.
Optionally, before detecting the grounding fault of the electrolytic cell group, detecting the grounding fault of the electrolytic cell group: and measuring the AC coupling loop current i of the electrolytic cell group under the condition that the AC excitation voltage is applied to the electrolytic cell group, and judging that the electrolytic cell group has the ground fault if the AC coupling loop current i of the electrolytic cell group is larger than a set value b.
Optionally, after the final determination of all the electrolytic cells with the ground faults, the method further comprises: checking the total number of the electrolytic cells with the ground faults, and if the total number is one, determining that the electrolytic cells with the ground faults are zero points of the electrolytic cell group.
Optionally, after the final determination of all the electrolytic cells with the ground faults, the method further comprises: checking the total number of the electrolytic cells with the ground faults, and if the total number is a plurality of electrolytic cells, determining that the electrolytic cells with the ground faults are zero points of the electrolytic cell group according to the following formula:
In the above formula, x is zero point of the electrolytic cell group, k is total number of electrolytic cells having ground fault, x m is position of any electrolytic cell #m, R m is ground resistance of the electrolytic cell #m, and m=1, 2, …, k.
Optionally, the calculation function expression of the grounding resistance of the electrolytic cell #m is:
In the above formula, R m is the grounding resistance of the electrolytic cell #m, U dm is the alternating voltage of the electrolytic cell #m, deltaI m is the difference between the resistive current I m of the electrolytic cell #m and the resistive current I m+1 of the adjacent electrolytic cell #m+1, wherein the alternating voltage of the electrolytic cell #m takes the value of the first-end alternating voltage of the electrolytic cell group.
Optionally, the calculation function expression of the difference between the resistive current I m of the electrolytic cell #m and the resistive current I m+1 of the adjacent electrolytic cell #m+1 is:
ΔIm＝Im-Im+1。
optionally, the calculation function expression of the resistive current I m of the electrolytic cell #m is:
In the above formula, i m is the alternating current of any electrolytic cell #m, N is the total number of electrolytic cells in the electrolytic cell group, m is the serial number of the electrolytic cell #m, and i c is the capacitance current to ground of the single electrolytic cell under alternating current excitation.
In addition, the invention also provides an electrolytic cell multipoint grounding detection system based on the injection signal voltage response, which comprises a microprocessor and a memory which are connected with each other, wherein the microprocessor is programmed or configured to execute the electrolytic cell multipoint grounding detection method based on the injection signal voltage response.
Furthermore, the invention provides a computer readable storage medium having stored therein a computer program for programming or configuring by a microprocessor to perform the method of cell multipoint ground detection based on injection signal voltage response.
Compared with the prior art, the invention has the following advantages: when the electrolytic tank group has a ground fault, alternating current excitation voltage is loaded to the electrolytic tank group, the alternating current voltage and the direct current voltage of each electrolytic tank are synchronously measured, the alternating current of the electrolytic tank is calculated, and the alternating currents of adjacent electrolytic tanks of each group are compared: if the alternating current i m of any electrolytic cell #m is larger than a times of the alternating current i m+1 of the electrolytic cell #m+1 adjacent to the electrolytic cell #m, judging that the electrolytic cell #m has a grounding fault, and finally determining all electrolytic cells with the grounding fault, wherein a is larger than 1.
Drawings
FIG. 1 is a schematic flow chart of a method according to an embodiment of the invention.
FIG. 2 is a DC equivalent circuit diagram of an electrolytic cell according to a first embodiment of the invention.
FIG. 3 is an alternate current equivalent circuit diagram of an electrolytic cell in accordance with a first embodiment of the present invention.
FIG. 4 is an alternate current equivalent circuit diagram of an electrolytic cell (#m cell having a ground fault and #m+1 cell having no ground fault) according to an embodiment of the present invention.
FIG. 5 is an alternate current equivalent circuit diagram of an electrolytic cell (#m tank having a ground fault) and (#m+1 tank having a ground fault) according to an embodiment of the present invention.
FIG. 6 is an alternate current equivalent circuit diagram of an electrolytic cell (#m cell having a ground fault and #m+1 cell having no fault, but the following cell having a ground fault) according to the first embodiment of the present invention.
FIG. 7 is an alternate current equivalent circuit diagram of an electrolytic cell (#mSlot has no fault and #m+1 has no ground fault) in accordance with an embodiment of the present invention.
FIG. 8 is an alternate current equivalent circuit diagram of an electrolytic cell (#m cell having no fault, #m+1 or ground fault at a later stage) according to an embodiment of the invention.
FIG. 9 is a detailed flow chart of a second method according to the present invention.
FIG. 10 is a circuit diagram of a multipoint earthing equivalent circuit of an electrolytic cell in a second embodiment of the invention.
FIG. 11 is a schematic circuit diagram of an electrolytic cell group in an embodiment of the invention.
Detailed Description
As shown in fig. 1, the method for detecting the multipoint earthing of the electrolytic cell based on the voltage response of the injection signal of the present embodiment comprises loading ac excitation voltage to the electrolytic cell group and synchronously measuring ac voltage and dc voltage of each electrolytic cell, calculating ac current of the electrolytic cell, and comparing ac current of each group of adjacent electrolytic cells in case that an earthing fault of the electrolytic cell group is detected: if the ac current i m of any cell #m is greater than a times the ac current i m+1 of the adjacent cell #m+1 (i m>aim+1), then it is determined that the cell #m has a ground fault, and finally all the cells having the ground fault are determined, where a is greater than 1, and thus i m>aim+1 can also be represented as i m>>im+1, as shown in fig. 2.
In this embodiment, when an ac excitation voltage is applied to the cell stack, an ac excitation source of 50Hz and 30V is selected, and a coupling capacitance of 1000 μf/1000V is applied to the head end of the cell stack or to the middle of the cell stack. The cell voltage sensor synchronously detects the effective values of the direct current voltage U of the electrolytic cell and the alternating current voltage U of the electrolytic cell, the data are transmitted remotely wirelessly, the sensor adopts a floating design, and the working power supply takes electricity on site. Detection precision: direct current voltage 1mV, alternating current voltage 1 mu V; the groove-to-ground voltage sensor detects the effective value of the groove-to-ground alternating voltage u d, data are transmitted remotely wirelessly, the sensor adopts a floating design, and a working power supply takes power on site. Detection precision: the ac voltage was 1mV. The direct current I s = 350kA of the electrolytic cell group, the direct current voltages at two sides of the electrolytic cell group are respectively +/-580V, the cell voltage is about 4.2V in normal operation, the cell resistance R 0 is about 1.2 multiplied by 10 -5 omega, and the resistance value fluctuates in normal operation; the insulation resistance R to the ground is larger than 5MΩ under normal condition, the distributed capacitance C to the ground is about 0.7-1.0nF, when the excitation frequency is 50Hz, the capacitance resistance Xc is about 3.2MΩ, the capacitance current to the ground is about 10 μA, and the total capacitance current to the ground of the whole electrolytic tank group is only 2.76mA.
The functional expression for calculating the alternating current of the electrolyzer in this embodiment is:
im＝umIs/Um，
In the above formula, I m represents an ac current of any cell #m, U m represents an ac voltage of the cell #m, I s represents a dc current of the cell group, and U m represents a dc voltage of the cell #m.
In this embodiment, detecting an earth fault in the cell stack further includes, prior to detecting an earth fault in the cell stack: and measuring the AC coupling loop current i of the electrolytic cell group under the condition that the AC excitation voltage is applied to the electrolytic cell group, and judging that the electrolytic cell group has the ground fault if the AC coupling loop current i of the electrolytic cell group is larger than a set value b. Specifically, in this embodiment, if the ac coupling loop current i of the cell group is greater than 10mA, it is determined that a ground fault is detected in the cell group. In addition, other ground fault determination methods may be employed as needed, and the method of the present embodiment is not dependent on a specific ground fault determination method.
The principle of comparing alternating currents of adjacent cells of each group to determine that the electrolytic cell #m has a ground fault based on the injection signal voltage response of the electrolytic cell multipoint ground detection method according to the embodiment is as follows:
1. a cell direct current system for an electrolysis cell group.
Single point ground condition: for a series direct current system, a direct current loop is not formed by single-point grounding, and no direct current voltage drop exists on a grounding resistor, so that the grounding point is a series zero point, and the direct current voltage of the groove is unchanged. Therefore, for a series of point ground faults, the positioning cannot be detected from the direct voltage of the electrolyzer, but rather from the tank-to-ground potential distribution, i.e. the zero drift.
Two or more multipoint earthing conditions:
The direct current equivalent circuit of the electrolytic cells is shown in fig. 2, and each electrolytic cell is equivalent to a parallel circuit of a resistor and a capacitor, wherein (a) shows a capacitor charging state, and (b) shows a capacitor discharging state. The direct current of each tank in front of the #m tank is I s, the direct current of the #m tank is I m, the direct current after the #m tank is I s-Im in the capacitor charging state, and the direct current after the #m tank is I s+Im in the capacitor discharging state. Taking two-point grounding as an example, grounding resistors of grounding electrolytic tanks (grounding tanks for short) are denoted by R m、Rn, and zero points of the series are necessarily arranged between the grounding tanks #m and #n, so that zero point positions x are arranged. Considering that the dc current I m、In of the grounded tank is negligible compared to 350kA, the tank voltage can be set to U 0 =4.2v.
Im+In＝0，
In the above formula, I m、In is the resistive current of the electrolytic cell #m and the electrolytic cell #n, x is the zero point of the electrolytic cell group, U 0 is the single cell voltage of the electrolytic cell, R m、Rn is the grounding resistance of the electrolytic cell #m and the electrolytic cell #n, and m and n are the serial numbers of the electrolytic cell #m and the electrolytic cell #n.
The rest of the multipoint-to-ground zero position algorithm is treated the same. ① The DC voltage of each tank in front of the #m tank is I sR0m, the DC voltage of each tank behind the #m tank is (the DC voltage of each tank in front of the #m tank is I s-Im)R0 m+1;② #n tank is I sR0n+1, thus the DC voltage of each tank behind the #n+1 tank is abrupt, the abrupt quantity is I mR0m, the maximum is mV grade, # n tank DC voltage is also abrupt, and the failure point position is calculated and can be ignored, wherein I s is the DC current of each tank in front of the #m tank, R 0m is the resistance of the electrolytic tank #m, R 0 m+1 is the resistance of the electrolytic tank #m+1, and R 0n is the resistance of the electrolytic tank #n.
2. A cell communication system for an electrolysis cell group.
The alternating current equivalent circuit of the electrolytic cell is shown in figure 3. Under ac excitation, the ac current flowing through the electrolyzer is typically composed of two parts, namely capacitive current to ground and resistive current. The #m tank ac current i m is the vector sum of the resistive current i Rm and the capacitive current (N-m) i c. The resistive current i Rm may be the ground current caused by the #m tank ground fault or the #m+1 rear tank ground current. Considering that i c is small, there are:
In the above formula, i m is an alternating current of any cell #m, i Rm is a resistance current of the cell #m, (N-m) i c is a capacitance current of the cell #m, N is the total number of cells of the cell group, m is a serial number of the cell #m, and i c is a capacitance current to ground of a single cell under alternating current excitation. Based on this, the alternating currents of each group of adjacent cells can be compared to determine the principle that cell #m has a ground fault. Under the action of an alternating current excitation source, the monitoring system detects the voltage U c at two ends of the coupling capacitor, and whether the series has a ground fault can be judged according to the change of the voltage. Coupling capacitance c=1000 μf, capacitive reactance xc=3.18Ω. ① When the series has no ground fault, the whole series only has a capacitance current Ni c to ground of about 1mA, and the voltage on the coupling capacitor is in mV level. ② When any slot has a ground fault, the voltage U c on the coupling capacitor, the voltage at the head end of the slot series is:
Where U c = 3.18i, i is the ac coupling loop current.
When the grounding resistance is 1kΩ, the current flowing through the coupling capacitor is more than 30mA, which is obviously increased compared with the series no-grounding fault condition, the smaller the grounding resistance is, the larger the voltage on the coupling capacitor is relatively, and the series grounding fault judgment can be realized by setting a proper threshold value. The sensor synchronously measures the direct current voltage U and the alternating current voltage U of the # m groove and the # m+1 groove, which are respectively denoted as U m、Um+1, U m and U m+1. Under ac excitation, #m tank ac current i m, resistive current i Rm and capacitive current (N-m) i c; a#m+1 tank ac current i m+1, a resistive current i Rm+1 and a capacitive current (N-m-1) i c. Considering that the tank-to-ground capacitance current i c is small, generally i c<<im. If the #m tank fails, the ac effective value i m、im+1 of the #m and #m+1 tanks can be calculated from the ac and dc components of the tank voltage.
Um＝Is×Rm0um＝im×Rm0
im＝umIs/Umi(m+1)＝um+1Is/Um+1
Under ac excitation, the ac current flowing through the electrolyzer is typically composed of two parts, namely capacitive current to ground and resistive current. There are several cases: ① The #m tank has a ground fault, and the #m+1 tank and the following tank have no ground fault, as shown in fig. 4. The #m tank ac current i m is the vector sum of the resistive current i Rm and the capacitive current (N-m) i c. Whereas the ac current of the #m+1 tank is only capacitive current, i.e.: i m+1＝(N-m-1)ic is small relative to i m. Therefore, this case must be: the i m>>im+1.② # m slot had a ground fault and the # m +1 slot had a ground fault, and the analysis is shown in figure 5. Obviously, i m≈iRm+iR(m+1), i m>im+1.③ #m had ground fault and #m+1 had no fault, but the following slot had ground fault, and the analysis is shown in fig. 6. by comparing and analyzing the end slots one by one, the ground fault of the slot #m can be analyzed and judged. The method is the same as that described above for ②. ④ The #m tank has no fault, and the #m+1 tank has no ground fault. The analysis is shown in fig. 7. Whether the rear slot is grounded or not, the two-slot alternating current has only one single-slot capacitance-to-ground current difference. Thus, i m is compared with i m+1. If i m≈im+1, then the #m slot has no ground fault. ⑤ The #m tank has no fault and the #m+1 or the rear has a ground fault. The analysis is shown in fig. 8. The ground current of the # m+1 slot also passes through the # m slot, and the alternating current of the two slots also has only a difference value of the capacitance current of the single slot to the ground. Thus, i m is compared with i m+1. If i m≈im+1, then the #m slot has no ground fault. In this embodiment, the detection accuracy of the ac voltage of the tank is 1 μv, the current difference Δi (1 μv×350 kA)/4.2v=0.083a between the two tanks, i.e. the ac current flowing through the grounding resistor is 0.083A, and the corresponding grounding resistor which can be distinguished by the system is 360 Ω. It is therefore seen that, The alternating currents of each set of adjacent cells may be compared to determine that cell #m has a ground fault: if the ac current i m of any one of the electrolytic cells #m is greater than a times (i m>aim+1) the ac current i m+1 of the electrolytic cell #m+1 adjacent to the electrolytic cell #m, it is determined that the electrolytic cell #m has a ground fault, All the cells in which the ground fault occurred were finally determined, where a was greater than 1.
Embodiment two:
This embodiment is a further improvement of the first embodiment, and referring to fig. 9, specifically, the first embodiment further adds the calculation process of the zero point of the electrolytic cell group on the basis of the first embodiment.
In this embodiment, after determining all the electrolytic cells with ground faults, the method further includes: checking the total number of the electrolytic cells with the ground faults, and if the total number is one, determining that the electrolytic cells with the ground faults are zero points of the electrolytic cell group. The total number of the electrolytic cells with the ground faults is one, namely the single-point ground condition. For the direct current system of the electrolytic cell group, a direct current loop is not formed by single-point grounding, and no direct current voltage drop exists on the grounding resistor, so that the grounding point is a series zero point.
In this embodiment, after determining all the electrolytic cells with ground faults, the method further includes: checking the total number of the electrolytic cells with the ground faults, and if the total number is a plurality of electrolytic cells, determining that the electrolytic cells with the ground faults are zero points of the electrolytic cell group according to the following formula:
In the above formula, x is zero point of the electrolytic cell group, k is total number of electrolytic cells having ground fault, x m is position of any electrolytic cell #m, R m is ground resistance of the electrolytic cell #m, and m=1, 2, …, k. In this embodiment, the ground resistance of the electrolytic cell #m is calculated as:
In the above formula, R m is the grounding resistance of the electrolytic cell #m, U dm is the alternating voltage of the electrolytic cell #m, deltaI m is the difference between the resistive current I m of the electrolytic cell #m and the resistive current I m+1 of the adjacent electrolytic cell #m+1, wherein the alternating voltage of the electrolytic cell #m takes the value of the first-end alternating voltage of the electrolytic cell group. In this embodiment, the calculation function expression of the difference between the resistive current I m of the electrolytic cell #m and the resistive current I m+1 of the adjacent electrolytic cell #m+1 is:
ΔIm＝Im-Im+1。
In this example, the resistive current I m of the electrolytic cell #m has a calculated functional expression:
In the above formula, i m is the alternating current of any electrolytic cell #m, N is the total number of electrolytic cells in the electrolytic cell group, m is the serial number of the electrolytic cell #m, and i c is the capacitance current to ground of the single electrolytic cell under alternating current excitation.
The total number of the electrolytic cells with the ground faults is a plurality of the electrolytic cells, namely the multi-point ground condition, and the equivalent circuit is shown in figure 10. Let zero point be at #x, electrolytic cells with ground fault (fault cell for short) be #m, #q, #n, #m, #q, #n the ground resistance of cell be R m、Rq、Rn respectively, resistive current be I m、Iq、In respectively, voltage to ground be U m、Uq、Un respectively, single cell voltage be U 0. Then there are: u m＝(x-m)U0、Uq＝(x-q)U0、Un＝(x-n)U0
Im+Iq+In＝0，
The other multipoint grounded zero point position algorithms are treated in the same way and can be expressed as determining that the electrolytic cell with the ground fault is the zero point of the electrolytic cell group according to the following formula:
In the above formula, x is zero point of the electrolytic cell group, k is total number of electrolytic cells having ground fault, x m is position of any electrolytic cell #m, R m is ground resistance of the electrolytic cell #m, and m=1, 2, …, k. By the method, alternating current excitation signals can be loaded on the electrolytic tank series, alternating current and direct current voltages of the electrolytic tank are measured, the orthogonality of capacitance current and resistance current is utilized to calculate leakage current and insulation resistance of the electrolytic tank, so that whether the electrolytic tank has a ground fault or not is judged, the ground fault is positioned, and zero drift is calculated.
In this example, ATPDraw was used for simulation, and the circuit model of the cell group is shown in fig. 11, and the cell group contains 276 cells, which are respectively denoted by #1 to #276, the resistance of each cell is 1.2x -5 Ω, the capacitance for insulation to ground and the parallel resistance are simulated, the resistance is 5mΩ, and the capacitance is 1nF. The AC excitation power supply is 30V/50Hz, the coupling capacitance is 1000 muF, and the power supply is a constant current source +/-350 kA at the head end of the loading series.
(1) Single point ground fault simulation.
Setting the #50 slot to have a grounding fault and a grounding resistance of 10Ω, and loading alternating voltage 28.589V at the head end of the series as shown in table 1, wherein the serial number of the grounding slot, the grounding resistance value and the series zero point position are all correct.
Table 1: single point ground fault simulation results.
(2) And (5) simulating multipoint ground faults.
① The grooves #10, #20 and #50 are grounded, and the grounding resistances are 10Ω,5Ω and 2Ω respectively. The simulation results are shown in Table 2. The alternating current voltage 10.968V added at the serial head end, the ground fault groove and the ground resistance are consistent with the setting, the zero point position is calculated as x=37.5 according to the formula (8), the simulation result #37 is 2.1369V to the ground potential, the simulation result #38 is-2.0627V to the ground potential, the serial zero point is between #37 and #38, and the simulation result shows that the algorithm is correct.
Table 2: the three-point ground fault simulation results (# 10, #20, # 50) set the ground resistances to 10Ω, 5Ω,2Ω.
② The ground resistances were changed, and the ground resistances of #10, #20, #50 were 20Ω,5Ω,20Ω, and the simulation results are shown in table 3 below. The AC voltage 21.638V is applied to the head end, and the AC voltage/current on the capacitor is 20.715V/6.5035A. From the coupling capacitance voltage it can be determined that a ground fault exists in the series. And calculating the fault slot and the grounding resistance of the fault slot by slot according to an algorithm, wherein the calculated zero point position is x=23.33, and the series zero points are between #23 and #24 slots. Simulation results show that the ground voltage of the #23 groove is 1.5112V, and the ground voltage of the #24 groove is-2.688V.
Table 3: the three-point ground fault simulation results (# 10, #20, # 50) set the ground resistances to 20Ω,5Ω,20Ω.
Therefore, the simulation result proves that the theoretical values of the first embodiment and the second embodiment are consistent, and the first embodiment and the second embodiment can be verified to effectively judge and analyze the sequence number of the grounding groove, the grounding resistance value and the series zero point position.
In addition, the embodiment also provides an electrolytic cell multipoint grounding detection system based on the injection signal voltage response, which comprises a microprocessor and a memory which are connected with each other, wherein the microprocessor is programmed or configured to execute the electrolytic cell multipoint grounding detection method based on the injection signal voltage response.
Furthermore, the present embodiment also provides a computer readable storage medium having stored therein a computer program for programming or configuring by a microprocessor to perform the method of cell multipoint ground detection based on injection signal voltage response.
It will be appreciated by those skilled in the art that embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-readable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein. The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks. These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks. These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above examples, and all technical solutions belonging to the concept of the present invention belong to the protection scope of the present invention. It should be noted that modifications and adaptations to the present invention may occur to one skilled in the art without departing from the principles of the present invention and are intended to be within the scope of the present invention.
Claims (9)
1. An electrolytic cell multipoint grounding detection method based on injection signal voltage response is characterized by comprising the following steps: when the grounding fault of the electrolytic cell group is detected, alternating current excitation voltage is loaded to the electrolytic cell group, alternating current voltage and direct current voltage of each electrolytic cell are synchronously measured, alternating current of the electrolytic cell is calculated, and alternating current of adjacent electrolytic cells of each group is compared: if the alternating current i m of any electrolytic cell #m is larger than a times of the alternating current i m+1 of the electrolytic cell #m+1 adjacent to the electrolytic cell #m, judging that the electrolytic cell #m has a ground fault, and finally determining all electrolytic cells with the ground fault, wherein a is larger than 1; the function expression for calculating the alternating current of the electrolytic cell is as follows:
im=umIs/Um，
In the above formula, I m represents an ac current of any cell #m, U m represents an ac voltage of the cell #m, I s represents a dc current of the cell group, and U m represents a dc voltage of the cell #m.
2. The method for multi-point ground detection of an electrolytic cell based on injected signal voltage response of claim 1, further comprising detecting a ground fault of the electrolytic cell group prior to detecting the ground fault of the electrolytic cell group: and measuring the AC coupling loop current i of the electrolytic cell group under the condition that the AC excitation voltage is applied to the electrolytic cell group, and judging that the electrolytic cell group has the ground fault if the AC coupling loop current i of the electrolytic cell group is larger than a set value b.
3. The method for detecting the multipoint earthing of the electrolytic cell based on the voltage response of the injection signal according to claim 1, wherein the final determining of all the electrolytic cells having the earthing fault further comprises: checking the total number of the electrolytic cells with the ground faults, and if the total number is one, determining that the electrolytic cells with the ground faults are zero points of the electrolytic cell group.
4. The method for detecting the multipoint earthing of the electrolytic cell based on the voltage response of the injection signal according to claim 1, wherein the final determining of all the electrolytic cells having the earthing fault further comprises: checking the total number of the electrolytic cells with the ground faults, and if the total number is a plurality of electrolytic cells, determining that the electrolytic cells with the ground faults are zero points of the electrolytic cell group according to the following formula:
，
In the above formula, x is zero point of the electrolytic cell group, k is total number of electrolytic cells having ground fault, x m is position of any electrolytic cell #m, R m is ground resistance of the electrolytic cell #m, and m=1, 2, …, k.
5. The method for detecting the multipoint earthing of the electrolytic cell based on the voltage response of the injection signal according to claim 4, wherein the calculation function expression of the earthing resistance of the electrolytic cell #m is:
，
In the above formula, R m is the grounding resistance of the electrolytic cell #m, U dm is the alternating voltage of the electrolytic cell #m, deltaI m is the difference between the resistive current I m of the electrolytic cell #m and the resistive current I m+1 of the adjacent electrolytic cell #m+1, wherein the alternating voltage of the electrolytic cell #m takes the value of the first-end alternating voltage of the electrolytic cell group.
6. The method for detecting the multipoint earthing of the electrolytic cell based on the voltage response of the injection signal according to claim 5, wherein a calculation function expression of a difference value between the resistive current I m of the electrolytic cell #m and the resistive current I m+1 of the adjacent electrolytic cell #m+1 is:
ΔIm=Im- Im+1。
7. The method for detecting the multipoint earthing of the electrolytic cell based on the voltage response of the injection signal according to claim 5, wherein the calculation function expression of the resistive current I m of the electrolytic cell #m is:
In the above formula, i m is the alternating current of any electrolytic cell #m, N is the total number of electrolytic cells in the electrolytic cell group, m is the serial number of the electrolytic cell #m, and i c is the capacitance current to ground of the single electrolytic cell under alternating current excitation.
8. An injection signal voltage response based electrolyzer multi-point ground detection system comprising a microprocessor and a memory interconnected, wherein the microprocessor is programmed or configured to perform the injection signal voltage response based electrolyzer multi-point ground detection method of any one of claims 1 to 7.
9. A computer readable storage medium having a computer program stored therein, wherein the computer program is for programming or configuring by a microprocessor to perform the method of electrolyzer multi-point ground detection based on injected signal voltage response of any one of claims 1 to 7.
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| CN112034283A (en) * | 2020-08-19 | 2020-12-04 | 重庆尚翔电气技术有限公司 | Device, system and process for detecting and positioning aluminum electrolysis cell ground fault |
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