Novel coal conveying belt operation protection system and method

Abstract

The invention relates to the technical field of power plant coal conveying programmed control systems, and provides a novel coal conveying belt operation protection system. The upper computer monitoring system software is connected with the programming controller system; the current monitoring module is used for monitoring the running current of the coal conveying belt; the differential module is connected with the current monitoring module and used for calculating the current change rate; the limit value alarm module is connected with the differential module and is used for triggering an alarm according to a comparison result of the current change rate and a preset threshold value; the limit value alarm module comprises a first alarm threshold value and a second alarm threshold value, the first alarm threshold value is used for giving an alarm prompt when the current change rate exceeds the threshold value, and the second alarm threshold value is used for automatically stopping belt operation when the current change rate exceeds the threshold value. By means of the technical scheme, the problem that in the prior art, a centralized controller cannot be reminded or automatic shutdown cannot be conducted, and consequently belt accidents are expanded is solved.

Description

Technical Field

[0001] The invention relates to the technical field of power plant coal conveying program control systems, and in particular to a novel coal conveying belt operation protection system and method. Background Art

[0002] The coal transportation system of power plants generally adopts a programmable controller (PLC) system, adopts a dual-machine hot standby mode, and uses duplex redundant cables to improve the reliability of system communication. As the upper computer monitoring system software of the programmable controller, the ifix monitoring system performs patrol collection, recording, fault voice alarm, and return control operations on a large amount of data in the programmable controller, and displays it in real time in the form of graphics or reports.

[0003] After actual application, it is found that this protection function that relies on the increase of the absolute value of current still has shortcomings, that is, it cannot protect the entire process of belt operation, especially the no-load and low-load stages at the beginning of operation. For example: when the belt is just started, the belt is in no-load and low-load operation, and the belt operation current is small. If coal foreign matter or equipment spare parts fall off and scratch or pierce the belt, at this time, although the belt current increases, the absolute value of the belt current does not reach the alarm value or shutdown value, and it is impossible to remind the centralized controller or automatically shut down, which causes the belt accident to expand. Summary of the invention

[0004] The present invention proposes a novel coal conveyor belt operation protection system and method, which solves the problem in the related technology that the centralized controller cannot be reminded or the machine cannot be automatically shut down, thereby causing the expansion of belt accidents.

[0005] The technical solution of the present invention is as follows:

[0006] A new type of coal conveyor belt operation protection system, including:

[0007] Programming controller system;

[0008] Host computer monitoring system software, connected to the programming controller system;

[0009] Current monitoring module, used to monitor the running current of the coal conveyor belt;

[0010] A differential module, connected to the current monitoring module, for calculating the current change rate;

[0011] A limit alarm module, connected to the differential module, for triggering an alarm according to a comparison result between the current change rate and a preset threshold value;

[0012] The limit alarm module includes a first alarm threshold and a second alarm threshold. The first alarm threshold is used to issue an alarm reminder when the current change rate exceeds the threshold, and the second alarm threshold is used to automatically stop the belt operation when the current change rate exceeds the threshold.

[0013] Optionally, the host computer monitoring system software includes an ifix monitoring system, and the ifix monitoring system includes:

[0014] ifixWorkspace, which is used to build graphical displays of windows and define connections to industrial controllers and other window applications;

[0015] ifix RunTime is used to display and complete the graphics windows and functions created in IfixWorkspace.

[0016] Optionally, the differential time of the differential module is set to 1 second.

[0017] Optionally, the first alarm threshold and the second alarm threshold of the limit alarm module can be adjusted according to different power and voltage levels of the coal conveyor belt.

[0018] A novel coal conveyor belt operation protection method comprises the following steps:

[0019] S1, monitor the running current of coal conveyor belt;

[0020] S2, calculate the current change rate;

[0021] S3, comparing the current change rate with a preset alarm threshold;

[0022] S4. According to the comparison result, if the current change rate exceeds the first alarm threshold, an alarm reminder is issued;

[0023] S5. If the current change rate exceeds the second alarm threshold, the belt operation is automatically stopped.

[0024] Optionally, the preset alarm threshold is determined based on the current change rate of the belt during a normal load-carrying stage and the current change rate in a fault condition.

[0025] Optionally, the preset alarm threshold includes an alarm recommendation value and a trip recommendation value, wherein the alarm recommendation value is 4 times the normal change rate and the trip recommendation value is 8 times the normal change rate.

[0026] Optionally, the steps are implemented by programming a controller system and a host computer monitoring system software.

[0027] Optionally, the calculation formula for the current change rate in step S2 is:

[0028]

[0029] Wherein, I(t) is the current value at time t, I(t-Δt) is the current value at time t-Δt, and Δt is the time interval, which is usually set to 1 second.

[0030] Optionally, the actual calculation formula of the current change rate in step S2 can be optimized by digital filtering and differential calculation. The following formula is a real-time calculation formula:

[0031] I'(t) = I(t) - I(t - Δt);

[0032]

[0033] Where Filter(I'(t)) is a digital filter function used to smooth the calculation result of the current change rate and reduce false alarms caused by measurement noise.

[0034] The working principle and beneficial effects of the present invention are:

[0035] In the present invention, a novel system and method for protecting the operation of a coal conveyor belt is proposed. When an unexpected situation occurs at the initial start-up or during the shutdown process of the belt and causes a sudden increase in the belt current, an alarm can be promptly issued to remind the controller, thereby discovering the fault early and avoiding the expansion of the belt fault. The present invention runs the absolute value alarm protection of the belt current and the belt current change rate protection in parallel, realizing all-round protection without blind spots in all stages of the belt operation, avoiding the expansion of belt accidents caused by special operating conditions, and reducing economic losses. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The preferred implementation modes will be described below in a clear and understandable manner with reference to the accompanying drawings to further illustrate the above-mentioned characteristics, technical features, advantages and implementation methods of the present invention.

[0037] Figure 1 This is the actual current curve when the belt fails;

[0038] Figure 2 This is a schematic diagram of the current curve when the belt fails;

[0039] Figure 3 This is the current change rate protection schematic diagram;

[0040] Figure 4 It is the belt current change rate protection logic diagram of the present invention;

[0041] Figure 5 This is the AI ​​quantity alarm setting screen;

[0042] Figure 6 This is a schematic diagram of the current curve when the belt fails (current change rate protection is activated).

[0043] In the figure: 1. programming controller system, 2. upper computer monitoring system software, 3. current detection module, 4. differential module, 5. limit alarm module, 6. first alarm threshold, 7. second alarm threshold. DETAILED DESCRIPTION

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0045] In order to simplify the drawings, only the parts related to the invention are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically shown, or only one of them is marked. In this article, "one" not only means "only one", but also means "more than one", and "several" includes "two" and "more than two".

[0046] In this document, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] In addition, in the description of the present application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0048] Reference Figure 1 to Figure 6 , is an embodiment of the present invention, and proposes

[0049] A new type of coal conveyor belt operation protection system, including:

[0050] Programming controller system;

[0051] Host computer monitoring system software, connected to the programming controller system;

[0052] Current monitoring module, used to monitor the running current of the coal conveyor belt;

[0053] A differential module, connected to the current monitoring module, for calculating the current change rate;

[0054] A limit alarm module, connected to the differential module, for triggering an alarm according to a comparison result between the current change rate and a preset threshold value;

[0055] The limit alarm module includes a first alarm threshold and a second alarm threshold. The first alarm threshold is used to issue an alarm reminder when the current change rate exceeds the threshold, and the second alarm threshold is used to automatically stop the belt operation when the current change rate exceeds the threshold.

[0056] Optionally, the host computer monitoring system software includes an ifix monitoring system, and the ifix monitoring system includes:

[0057] ifixWorkspace, which is used to build graphical displays of windows and define connections to industrial controllers and other window applications;

[0058] ifix RunTime is used to display and complete the graphics windows and functions created in IfixWorkspace.

[0059] Optionally, the differential time of the differential module is set to 1 second.

[0060] Optionally, the first alarm threshold and the second alarm threshold of the limit alarm module can be adjusted according to different power and voltage levels of the coal conveyor belt.

[0061] A novel coal conveyor belt operation protection method comprises the following steps:

[0062] S1, monitor the running current of coal conveyor belt;

[0063] S2, calculate the current change rate;

[0064] S3, comparing the current change rate with a preset alarm threshold;

[0065] S4. According to the comparison result, if the current change rate exceeds the first alarm threshold, an alarm reminder is issued;

[0066] S5. If the current change rate exceeds the second alarm threshold, the belt operation is automatically stopped.

[0067] Optionally, the preset alarm threshold is determined based on the current change rate of the belt during a normal load-carrying stage and the current change rate in a fault condition.

[0068] Optionally, the preset alarm threshold includes an alarm recommendation value and a trip recommendation value, wherein the alarm recommendation value is 4 times the normal change rate and the trip recommendation value is 8 times the normal change rate.

[0069] Optionally, the steps are implemented by programming a controller system and a host computer monitoring system software.

[0070] Optionally, the calculation formula for the current change rate in step S2 is:

[0071]

[0072] Here, I is the current value at time t, I(t-Δt) is the current value at time t-Δt, and Δt is the time interval, which is usually set to 1 second.

[0073] Optionally, the actual calculation formula of the current change rate in step S2 can be optimized by digital filtering and differential calculation. The following formula is a real-time calculation formula:

[0074] I'(t) = I(t) - I(t - Δt);

[0075]

[0076] Where Filter(I'(t)) is a digital filter function used to smooth the calculation result of the current change rate and reduce false alarms caused by measurement noise.

[0077] Example: A coal conveyor belt in a power plant once had an accident where the belt was scratched for more than 100 meters (the actual current trend is as follows Figure 1 , the simulation schematic diagram is shown in Figure (2).

[0078] The main reason is that when the belt is running under a lower load (coal volume), the current fluctuates between 110-120A (the full load current is about 150A), and the coal baffle in the coal drop pipe is loose and suddenly falls off with the coal flow. One of its edges penetrates the belt, causing the current to suddenly rise to 145A and begin to tear the belt. Although the current increased at this time, it did not reach the set alarm value of 200A, and did not attract the attention of the controller. Later, when the load gradually increased and reached the alarm value, the controller discovered it and stopped the belt. At this time, the accident had already expanded, causing large economic losses and affecting the normal coal loading of the coal transportation system.

[0079] Through comparative calculation, the current change rate is calculated to be 1.2-1.5A / s during the normal load stage of the belt, and the current change rate during a sudden fault is 15-20A / s, which is very different and can be easily distinguished through the control system software. Therefore, the above theoretical and practical basis provides data support for a new system and method for protecting the operation of coal conveyor belts proposed in the present invention.

[0080] Protection logic diagram Figure 3, add a differential link function module to the PLC current analog input terminal, and set the differential time to 1 second to measure and calculate the rate of change of the current parameter. After the differential link, add a limit alarm function module. The change rate alarm value can be set on site according to the actual parameters such as the different powers and voltage levels of the coal conveyor belt. It is used to distinguish whether it is an equipment failure or an increase in load. If the current change rate exceeds the set value I, the system will issue an alarm to attract the attention of the controller and take timely measures; if the current change rate exceeds the set value II, the system will immediately stop the belt operation. See the logic block diagram Figure 4 .

[0081] Experimental steps:

[0082] 1. Calculate the normal current change rate value based on the current change trend of the belt during normal load-carrying process.

[0083] 2. Collect the current change trend under fault conditions and calculate the current change rate under fault conditions.

[0084] 3. Set the alarm value (as shown in Table 1) according to the power, lifting angle of different belts, and the current change rate under normal and fault conditions collected.

[0085] Belt current change rate parameter collection table

[0086]

[0087]

[0088] 4. Use administrator privileges to import alarm setting data into the control system for testing, such as Figure 5 , and continuously correct the alarm value according to the actual situation.

[0089] Configure alarm: For AI quantity alarm, configure as shown in the figure below, check "Enable alarm processing", configure "Alarm area" and alarm threshold, etc.

[0090] The present invention operates the absolute value alarm protection of the belt current and the belt current change rate protection in parallel, thus realizing all-round protection without blind spots in all stages of belt operation, avoiding the expansion of belt accidents caused by special operating conditions, and reducing economic losses.

[0091] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A new type of coal conveyor belt operation protection system, characterized in that: include: Programmable controller system (1); The upper computer monitoring system software (2) is connected to the programming controller system (1); A current monitoring module (3), used to monitor the operating current of the coal conveyor belt; A differential module (4), connected to the current monitoring module (3), and used for calculating the current change rate; A limit value alarm module (5), connected to the differential module (4), and used to trigger an alarm according to a comparison result between the current change rate and a preset threshold value; The limit value alarm module (5) comprises a first alarm threshold (6) and a second alarm threshold (7), wherein the first alarm threshold (6) is used to issue an alarm reminder when the current change rate exceeds the threshold, and the second alarm threshold is used to automatically stop the belt operation when the current change rate exceeds the threshold.

2. The system according to claim 1, characterized in that The host computer monitoring system software (2) includes an ifix monitoring system, and the ifix monitoring system includes: ifixWorkspace, which is used to build graphical displays in windows and define connections to industrial controllers and other window applications; ifix RunTime is used to display and complete the graphics windows and functions created in IfixWorkspace.

3. The system according to claim 1 or 2, characterized in that: The differential time of the differential module (4) is set to 1 second.

4. The system according to any one of claims 1 to 3, characterized in that: The first alarm threshold (6) and the second alarm threshold (7) of the limit alarm module (5) can be adjusted according to different power and voltage levels of the coal conveyor belt.

5. A new type of coal conveyor belt operation protection method, characterized in that: The following steps are involved: S1. Monitor the running current of coal conveyor belt; S2, calculate the current change rate; S3, comparing the current change rate with a preset alarm threshold; S4. According to the comparison result, if the current change rate exceeds the first alarm threshold (6), an alarm reminder is issued; S5. If the current change rate exceeds the second alarm threshold (7), the belt operation is automatically stopped.

6. The method according to claim 5, characterized in that The preset alarm threshold is determined based on the current change rate of the belt during the normal load-carrying stage and the current change rate under fault conditions.

7. The method according to claim 5 or 6, characterized in that: The preset alarm threshold includes an alarm recommendation value and a trip recommendation value, wherein the alarm recommendation value is 4 times the normal change rate, and the trip recommendation value is 8 times the normal change rate.

8. The method according to any one of claims 5 to 7, characterized in that: The steps are implemented by means of a programming controller system (1) and a host computer monitoring system software (2).

9. The method according to any one of claims 5 to 7, characterized in that: The calculation formula of the current change rate in step S2 is: Wherein, I(t) is the current value at time t, I(t-Δt) is the current value at time t-Δt, and Δt is the time interval, which is usually set to 1 second.

10. The method according to any one of claims 5 to 7, characterized in that: The actual calculation formula of the current change rate in step S2 can be optimized by digital filtering and differential calculation. The following formula is a real-time calculation formula: I'(t) = I(t) - I(t - Δt); Where Filter(I'(t)) is a digital filter function used to smooth the calculation result of the current change rate and reduce false alarms caused by measurement noise.

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