Multi-point grounding detection system and method for polycrystalline silicon reduction furnace
By real-time detection and logical judgment of grounding current fluctuations, the accuracy problem of multi-point grounding detection in polysilicon reduction furnaces has been solved, enabling early warning and protection, and avoiding equipment damage and production accidents caused by multi-point grounding.
Patent Information
- Application Number
- CN202511054528.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-30
- Publication Date
- 2025-11-18
AI Technical Summary
Existing technology cannot effectively detect whether there are two or more grounding points on the silicon rods inside the polysilicon reduction furnace, which would cause the operating current to form a loop, damaging the furnace barrel or furnace bottom, resulting in system interruption or damage to the reduction furnace.
By real-time detection of the magnitude and fluctuation of grounding current, combined with logical judgment of the number of fluctuations of grounding current per unit time, and utilizing the rate of change of grounding current and operating voltage, a multi-dimensional cross-validation logical judgment system is constructed to achieve early identification and protection of multi-point grounding.
It improves the stability of polysilicon production, prevents catastrophic damage caused by multiple grounding points, reduces unplanned downtime, and ensures production safety and product quality.
Smart Images
Figure CN120972035A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of polysilicon production technology, specifically relating to a multi-point grounding detection system and method for polysilicon reduction furnaces. Background Technology
[0002] The polysilicon reduction furnace is a crucial piece of equipment in polysilicon production. During polysilicon production through the reduction furnace, due to process control issues and furnace loading defects, problems such as excessive silicon powder on the bottom plate, amorphous silicon growth on the graphite base, and silicon rods hitting the furnace walls are inevitable, leading to grounding issues. If two or more points of grounding occur in a group of silicon rods within the reduction furnace, the operating current flows from the silicon rods to the furnace barrel, forming a loop and causing continuous discharge damage to the furnace barrel or bottom plate. This can lead to system interruption or damage to the reduction furnace, significantly impacting the company's production and operations and severely restricting the safety of polysilicon production. Therefore, providing a reliable and stable multi-point grounding detection method is of paramount importance.
[0003] Existing invention patent CN110702968B discloses a method for detecting grounding current in a polysilicon reduction furnace power supply system. Based on the different constant current sustaining voltages required at different stages of silicon core growth, the sustaining voltage is set in different levels, with each level having a corresponding warning value and action value for the grounding current. The warning value is lower than the action value. When the grounding current corresponding to the sustaining voltage reaches the warning value, an alert is issued, and the operator adjusts process parameters accordingly to avoid or delay the grounding current from reaching the action value. When the grounding current corresponding to the sustaining voltage reaches the action value, the operation of the polysilicon reduction furnace power supply system is stopped. However, all current technical solutions cannot detect whether there are two or more grounding points on the silicon rods. When two or more grounding points occur on a group of silicon rods in the reduction furnace, the operating current flows from the silicon rods to the furnace barrel, forming a loop. This will cause continuous discharge damage to the furnace barrel or furnace bottom, leading to system interruption or damage to the reduction furnace. Summary of the Invention
[0004] The purpose of this invention is to address the problems of existing technologies by providing a multi-point grounding detection system and method for polysilicon reduction furnaces. This system uses real-time monitoring of the grounding current of silicon rods within the furnace and the number of fluctuations within a set range per unit time to logically determine whether multi-point grounding exists. Furthermore, it uses sudden changes in operating current relative to a given current to logically assess the severity of multi-point grounding. Since the rate of change of the silicon rod's normal operating voltage gradually decreases, if multi-point grounding occurs due to furnace chassis erosion, electrode chassis damage accompanied by grounding current and a decrease in voltage of other phases, the program logically determines the presence of multi-point grounding within the furnace. Implementing this technology improves the accuracy and protection range of silicon rod grounding detection, allows for early detection of anomalies during operation to prevent accidents from escalating, and enhances the stability of polysilicon production.
[0005] This invention is achieved through the following technical solution: A multi-point grounding detection system for a polycrystalline silicon reduction furnace includes an electrically connected power regulation module, a silicon core load, a switching contactor, a high-voltage boost module, a grounding current detection module T80, a silicon rod voltage detection module, a power regulation control cabinet, and a grounding resistor.
[0006] Preferably, five grounding resistors are provided.
[0007] Preferably, the resistance of the grounding resistor is 1000Ω.
[0008] A method for detecting multi-point grounding in a polycrystalline silicon reduction furnace is proposed. The method uses real-time detection of grounding current, grounding current fluctuation range, and the number of grounding current fluctuations per unit time to logically determine whether multi-point grounding has occurred in the furnace. The fault judgment threshold is that the grounding current is greater than or equal to the minimum grounding current under the current voltage and the negative fluctuation of the grounding current exceeds the set range. If the grounding current reaches the set number of times within the set time, it is determined that two-point grounding discharge arcing has occurred, and the power supply of the corresponding phase power cabinet trips.
[0009] Preferably, the grounding current I d Real-time detection by T80, U l The operating voltage is monitored in real time by PT1 or PT2, and the grounding resistance R d The current is 5000Ω, and the operating current I is detected in real time by T60 or T70.
[0010] Preferably, when a certain phase grounding current I d ≥U l / R d If the negative fluctuation of the grounding current exceeds the set range and reaches the set number of times within the set time, it is determined that a two-point grounding discharge arc has occurred, and the power cabinet of that phase is interlocked and stopped.
[0011] Preferably, the range of the negative fluctuation of the grounding current is -I. d / 2~-I d The set time is 1 minute to 5 minutes; the set number of times is 5 to 10 times.
[0012] Preferably, when the operating current is greater than a set multiple of the current given current and the grounding current is greater than or equal to the ratio of the current operating voltage to the grounding resistance of the N pairs of rods, it is determined that multiple grounding has occurred in the furnace, and the power supply of the corresponding phase power cabinet trips.
[0013] Preferably, the operating current is greater than the current given current by a set multiple: that is, I ≥ (1.4~2)I 给定 ;I d ≥U l / N*R dThe PLC program determines that a two-point grounding discharge arc has occurred and interlocks to stop the power cabinet of that phase; where N is the number of pairs of load silicon rods of that power cabinet.
[0014] Preferably, the grounding current of a certain phase is judged by the ratio of the current operating voltage to the grounding resistance of the N pairs of rods, and the change rate of the operating voltage of any other phase in the previous 5 to 10 seconds is judged by the change rate of the operating voltage in the next 5 to 10 seconds; if the grounding current is greater than or equal to the ratio of the current operating voltage to the grounding resistance of the N pairs of rods and the change rate of the operating voltage of any other phase in the previous 5 to 10 seconds is less than the change rate of the operating voltage in the next 5 to 10 seconds, it is judged that multiple grounding arcing has occurred in the furnace, and the power supply of the corresponding phase power cabinet trips.
[0015] Compared with the prior art, the present invention has the following advantages and beneficial effects: I. This invention provides a method for detecting multi-point grounding in a polysilicon reduction furnace. It uses real-time monitoring of the grounding current of the silicon rods within the furnace and the number of fluctuations within a set range per unit time to logically determine whether multi-point grounding exists. Furthermore, it uses sudden changes in the operating current and a given current to logically assess the furnace condition based on the severity of the multi-point grounding. Since the rate of change of the silicon rod's normal operating voltage gradually decreases, if multi-point grounding occurs due to furnace chassis erosion, electrode chassis damage accompanied by grounding current and a decrease in voltage of other phases, the program logically determines the presence of multi-point grounding within the furnace. Implementing this technology improves the accuracy and protection range of silicon rod grounding detection, allows for early detection of anomalies during operation to prevent accidents from escalating, and enhances the stability of polysilicon production. II. The present invention provides a multi-point grounding detection method for polycrystalline silicon reduction furnaces, enabling early warning and intervention: It can detect multi-point grounding faults in their early stages or at a relatively mild stage (such as only abnormal fluctuations or slight current changes), triggering alarms or protection actions. This provides operators with a valuable intervention window, or the system can automatically perform initial adjustments.
[0016] Third, the present invention provides a multi-point grounding detection method for polycrystalline silicon reduction furnaces to prevent catastrophic consequences: through early diagnosis and interlocking protection, it effectively prevents the escalation of faults. In particular, it prevents irreversible ablation damage to the furnace chassis and electrodes caused by high-current arcs due to multi-point grounding, and also avoids silicon rod damage or even more serious production safety accidents (such as furnace body damage) that may be caused by this.
[0017] IV. The present invention provides a method for detecting multi-point grounding in a polycrystalline silicon reduction furnace. By monitoring the number of fluctuations in the grounding current per unit time in real time (whether it exceeds the set range), it can capture the characteristics of unstable and repeatedly changing grounding status. This is a typical sign of multi-point grounding (especially in the early and slight stages), which significantly improves the ability to identify early and slight multi-point grounding.
[0018] V. This invention provides a multi-point grounding detection method for polycrystalline silicon reduction furnaces. It combines current mutation analysis (comparing operating current to a given current) and voltage change rate / three-phase voltage anomaly analysis (disruption of the normal operating voltage change rate pattern coupled with simultaneous decreases in multi-phase voltage), constructing a multi-dimensional, cross-validated logical judgment system. This significantly improves the accuracy and reliability of diagnosis, effectively avoids misjudgment based on a single signal, and more accurately reflects the number and severity of grounding points (broader protection range).
[0019] VI. The present invention provides a multi-point grounding detection method for polycrystalline silicon reduction furnaces. By detecting and handling anomalies in advance, many potential major faults are nipped in the bud, significantly reducing long-term and costly unplanned downtime caused by severe chassis erosion, etc. Timely identification and handling of early grounding problems helps maintain the stability of the electric field in the reduction furnace and the uniformity of the thermal field during silicon rod growth, thereby ensuring the stable operation of polycrystalline silicon production and improving product quality and consistency. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the detection system in this invention.
[0021] Figure 2 This is a schematic diagram of the control system in the detection system of this invention. Detailed Implementation
[0022] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto.
[0023] The grounding principle is that when a single-point grounding occurs, the current returns to the N pole through the grounding resistor. Because the grounding resistor in series in the circuit limits the magnitude of the grounding current, the maximum current of a single-point grounding is equal to the grounding point voltage / grounding resistance, and the current is relatively small. When a hard grounding occurs at two points in the same phase, it is equivalent to the silicon rod between the two points being connected in parallel with the furnace bottom plate. Because the resistance of the furnace bottom plate is small, most of the operating current flows through the furnace bottom plate and returns from the next grounding point. This can cause arcing between the electrode and the furnace bottom plate, melting the electrode and the bottom plate, which will lead to a large system interruption or damage to the reduction furnace. Because the operating voltage changes and the grounding location is different, the magnitude of the grounding current cannot fully reflect the severity of the furnace bottom plate grounding. Therefore, PLC program interlocking or alarms should be added to the power supply system.
[0024] Example 1 like Figure 1As shown, a multi-point grounding detection system for a polycrystalline silicon reduction furnace includes a power regulation module, a silicon core load, a switching contactor, a high-voltage boost module, a grounding current detection module T80, a silicon rod voltage detection module, a power control cabinet, and a grounding resistor, all electrically connected.
[0025] like Figure 2 As shown, the controller TPC is electrically connected to PT1, PT2, operating current detection modules T60 / T70 and ground current detection module T80 respectively. The controller TPC is connected to the PLC through Profinet, and the PLC is electrically connected to the switching contactor.
[0026] Example 2 like Figure 1 As shown, a multi-point grounding detection system for a polycrystalline silicon reduction furnace includes a power regulation module, a silicon core load, a switching contactor, a high-voltage boost module, a grounding current detection module T80, a silicon rod voltage detection module, a power control cabinet, and a grounding resistor, all electrically connected.
[0027] Five grounding resistors are provided. These grounding resistors include R101, R102, R103, R104, and R105.
[0028] The grounding resistor has a resistance of 1000Ω. The resistors R101, R102, R103, R104, and R105 all have a resistance of 1000Ω.
[0029] Example 3 This embodiment uses the detection method of a multi-point grounding detection system for a polycrystalline silicon reduction furnace as described in Embodiment 2. The system uses real-time detection of grounding current and grounding current fluctuation range, as well as the number of grounding current fluctuations per unit time, to logically determine whether multi-point grounding has occurred in the furnace. The fault judgment threshold is that the grounding current is greater than or equal to the minimum grounding current under the current voltage and the negative fluctuation of the grounding current exceeds the set range. If the grounding current reaches the set number of times within the set time, it is determined that two-point grounding discharge arcing has occurred, and the power supply of the corresponding phase power cabinet trips.
[0030] Example 4 This embodiment uses the detection method of a multi-point grounding detection system for a polycrystalline silicon reduction furnace as described in Embodiment 2. The system uses real-time detection of grounding current and grounding current fluctuation range, as well as the number of grounding current fluctuations per unit time, to logically determine whether multi-point grounding has occurred in the furnace. The fault judgment threshold is that the grounding current is greater than or equal to the minimum grounding current under the current voltage and the negative fluctuation of the grounding current exceeds the set range. If the grounding current reaches the set number of times within the set time, it is determined that two-point grounding discharge arcing has occurred, and the power supply of the corresponding phase power cabinet trips.
[0031] Wherein, the grounding current I d Real-time detection by T80, Ul The operating voltage is monitored in real time by PT1 or PT2, and the grounding resistance R d The current is 5000Ω, and the operating current I is detected in real time by T60 or T70.
[0032] Among them, when a certain phase grounding current I d ≥U l / R d If the negative fluctuation of the grounding current exceeds the set range and reaches the set number of times within the set time, it is determined that a two-point grounding discharge arc has occurred, and the power cabinet of that phase is interlocked and stopped.
[0033] The range of the negative fluctuation of the grounding current is -I. d / 2~-I d The set time is 1 minute to 5 minutes; the set number of times is 5 to 10 times.
[0034] When the operating current is greater than the current given current by a set multiple and the grounding current is greater than or equal to the ratio of the current operating voltage to the grounding resistance of the N pairs of rods, it is determined that multiple grounding has occurred in the furnace, and the power supply of the corresponding phase power cabinet will trip.
[0035] Among them, the current given current that is greater than the set multiple is: that is, I ≥ (1.4~2)I 给定 ;I d ≥U l / N*R d The PLC program determines that a two-point grounding discharge arc has occurred and interlocks to stop the power cabinet of that phase; where N is the number of pairs of load silicon rods of that power cabinet.
[0036] The method involves determining the grounding current of a certain phase by comparing it with the ratio of the current operating voltage to the grounding resistance of the N pairs of rods, and also by comparing the rate of change of the operating voltage of any other phase in the previous 5-10 seconds with the rate of change of the operating voltage in the following 5-10 seconds. If the grounding current is greater than or equal to the ratio of the current operating voltage to the grounding resistance of the N pairs of rods, and the rate of change of the operating voltage of any other phase in the previous 5-10 seconds is less than the rate of change of the operating voltage in the following 5-10 seconds, then it is determined that multiple grounding arcing has occurred in the furnace, and the power supply of the corresponding phase power cabinet will trip.
[0037] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.
Claims
1. A multi-point grounding detection system for a polycrystalline silicon reduction furnace, characterized in that: It includes a power regulation module with electrical connections, a silicon core load, a switching contactor, a high-voltage boost module, a ground current detection module, a silicon rod voltage detection module, a power control cabinet, and a grounding resistor.
2. The multi-point grounding detection system for a polycrystalline silicon reduction furnace according to claim 1, characterized in that: Five grounding resistors are provided.
3. The multi-point grounding detection system for a polycrystalline silicon reduction furnace according to claim 2, characterized in that: The resistance of the grounding resistor is 1000Ω.
4. The detection method of a multi-point grounding detection system for a polycrystalline silicon reduction furnace according to any one of claims 1-3, characterized in that: The system uses real-time detection of grounding current and its fluctuation range, as well as the number of grounding current fluctuations per unit time, to logically determine whether multiple grounding points have occurred inside the furnace. The fault judgment threshold is that the grounding current is greater than or equal to the minimum grounding current under the current voltage and the negative fluctuation of the grounding current exceeds the set range. If the grounding current reaches the set number of times within the set time, it is determined that two-point grounding discharge arcing has occurred, and the power supply of the corresponding phase power cabinet will trip.
5. The method for detecting multi-point grounding in a polycrystalline silicon reduction furnace according to claim 4, characterized in that: The grounding current I d Real-time detection by T80, U l The operating voltage is detected in real time by PT1 or PT2, and the grounding resistance R d The current is 5000Ω, and the operating current I is detected in real time by T60 or T70.
6. The method for detecting multi-point grounding in a polycrystalline silicon reduction furnace according to claim 5, characterized in that: When a certain phase grounding current I d ≥U l / R d If the negative fluctuation of the grounding current exceeds the set range and reaches the set number of times within the set time, it is determined that a two-point grounding discharge arc has occurred, and the power cabinet of that phase is interlocked and stopped.
7. The method for detecting multi-point grounding in a polycrystalline silicon reduction furnace according to claim 6, characterized in that: The range of negative fluctuation in the grounding current is -I. d / 2~-I d The set time is 1 minute to 5 minutes; the set number of times is 5 to 10 times.
8. The method for detecting multi-point grounding in a polycrystalline silicon reduction furnace according to claim 7, characterized in that: If the operating current is greater than the current given current by a set multiple and the grounding current is greater than or equal to the ratio of the current operating voltage to the grounding resistance of the N pairs of rods, it is determined that multiple grounding points have occurred in the furnace, and the power supply of the corresponding phase power cabinet will trip.
9. A method for detecting multi-point grounding in a polycrystalline silicon reduction furnace according to claim 8, characterized in that: The current given current that is greater than a set multiple is: i.e., I ≥ (1.4~2)I. 给定 ;I d ≥U l / N*R d The PLC program determines that a two-point grounding discharge arc has occurred and interlocks to stop the power cabinet of that phase; where N is the number of pairs of load silicon rods of that power cabinet.
10. A method for detecting multi-point grounding in a polycrystalline silicon reduction furnace according to claim 9, characterized in that: The grounding current of a certain phase is judged by the ratio of the current operating voltage to the grounding resistance of the N-pair grounding rods, and the change rate of the operating voltage of any other phase in the previous 5-10 seconds is judged by the change rate of the operating voltage in the next 5-10 seconds. If the grounding current is greater than or equal to the ratio of the current operating voltage to the grounding resistance of the N-pair grounding rods, and the change rate of the operating voltage of any other phase in the previous 5-10 seconds is less than the change rate of the operating voltage in the next 5-10 seconds, it is judged that multiple grounding arcing has occurred in the furnace, and the power supply of the corresponding phase power cabinet trips.