Multi-pump displacement compensation control method and system based on pre-calculation

Abstract

The invention relates to the technical field of oil and gas field development yield increase operation fracturing construction, and discloses a multi-pump displacement compensation control method based on precomputation, which comprises the following steps of: configuring the load grade, the rated displacement and the maximum displacement of each pump skid; calculating an online standby margin; when a pump skid breaks down, displacement compensation is calculated; and calculating to obtain the calculated displacement of all the on-line pump skid, and executing compensation. The invention further discloses a multi-pump displacement compensation control system based on pre-calculation. According to the multi-pump displacement compensation control method and system based on pre-calculation, the problem of displacement fluctuation caused by pump skid shutdown in fracturing construction is solved, and the construction stability, the equipment utilization rate and the automation level are improved.

Description

Technical Field

[0001] This invention relates to the field of fracturing construction technology for oil and gas field development and production enhancement operations, specifically to a multi-pump displacement compensation control method based on pre-calculation. Background Technology

[0002] At present, oilfield drilling technology has made rapid progress both at home and abroad. Oil and gas development has gradually extended from conventional large oilfields and gas fields to unconventional and difficult-to-access oil and gas fields. The difficulty of oilfield development is gradually increasing. Low permeability and high viscosity, complex extraction technology, and frequent construction and production enhancement measures are the most prominent characteristics of unconventional oil and gas development.

[0003] Currently, the development of various oil and gas fields has gradually shifted towards the development of marginal oil and gas fields. During the development of marginal oil and gas fields, due to limited economic value and overall budget, the development process is extremely sensitive to issues such as equipment costs, operation and maintenance, management, and energy conservation. With the deepening of unconventional oil and gas resource development, fracturing operations increasingly rely on the joint operation of multiple high-power pump skids. However, traditional control methods are mostly manual or single-pump independent control, which has the following drawbacks: 1. To ensure reliability, multiple pieces of equipment are often put into operation at the same time, usually requiring a large number of online backup pump skids. This results in the equipment's efficiency not being fully utilized. Due to the large power of the equipment, there is a serious loss of power consumption, leading to high equipment investment and energy waste. 2. An unexpected shutdown of any pump skid will cause a sharp drop in total discharge, affecting the crack propagation effect and reducing production efficiency; 3. Due to differences in service life and maintenance conditions, the performance of pump skids varies significantly, making unified scheduling difficult; 4. Operators need to monitor and manually intervene in real time, which is labor-intensive and has a slow response time.

[0004] Traditional control methods are no longer sufficient to meet the needs of oilfields for low-cost, low-pollution, green and environmentally friendly, and high-efficiency development. There is a lack of intelligent collaborative control strategies that can predict in advance, automatically compensate, and accurately allocate resources. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of the above-mentioned technologies by providing a pre-calculated multi-pump displacement compensation control method and system, which solves the displacement fluctuation problem caused by pump skid shutdown during fracturing operations, and improves construction stability, equipment utilization and automation level.

[0006] To achieve the above objectives, the multi-pump displacement compensation control method based on pre-calculation designed in this invention includes the following steps: S1) Configure the load level, rated displacement and maximum displacement of each pump skid. The load level I includes level 1, level 2, ..., level i, where level 1 is the lowest, indicating the weakest performance of the pump skid, and level i is the highest, indicating the best performance. S2) Calculate the online reserve margin A=P e -P x-set -P avg-line In the formula, P e P represents the total rated displacement of the online pump skid. x-set To design the required total displacement for operation phase x, P avg-line The average displacement of a single pump skid in the online system is given. If A > 0, proceed to step S3. If A ≤ 0, meaning the online backup capacity is insufficient, the system alarms and the command center activates the backup pump skid. S3) Perform displacement compensation pre-calculation; S4) Load level I=1; S5) Calculate the compensation base B under the current load level I. I =(P x-set -P online ) / N I In the formula, P online N represents the total real-time discharge of the online pump skid. I The total number of online pump skids shall not be less than the current load level I; S6) Obtain the calculated displacement P of the online pump skid at the current load level. n-c =P n +B I P n This represents the real-time discharge capacity of the nth pump skid. S7) If P n-c ≤P n-max P n-max If the maximum displacement is set for the nth pump skid, proceed to step S8). n-c >P n-max (I = I + 1, return to step S5) until P is satisfied. n-c ≤P n-max If the load level is i, it still cannot satisfy P. n-c ≤P n-max If the hot standby pump capacity is insufficient, the system will alarm and the command center will activate the standby pump skid. S8) Calculate the calculated displacement P of all online pump skids. n-c =P n +B I When a fault occurs, compensation is performed.

[0007] Preferably, after the compensation is performed, the compensation error K=|P online -P x-set | / P x-set If K≤M, where M is the compensation accuracy, it is considered normal. If K>M, then the error accuracy compensation L=(P) is calculated. online -P k-set ) / N IFor each pump skid, error accuracy compensation L is performed.

[0008] Preferably, the compensation accuracy is less than or equal to 0.5%.

[0009] Preferably, when the number of pump skids in operation is less than the minimum number of pump skids in operation, the system will alarm and the command center will activate the backup pump skids.

[0010] Preferably, based on the number of online pump skids, the offline 1, 2, 3, etc., are calculated sequentially. The compensation amount is calculated up to the minimum number of online pump skids, and the results are marked on the system. When the system conditions are triggered, the system directly compensates with the displacement based on the calculated results.

[0011] A pre-calculated multi-pump displacement compensation control system includes: several pump skids, each equipped with an independent control system; The high-voltage VFD electric drive system adopts a "one-to-two" structure, with a single high-voltage VFD electric drive system driving two pump skids. The command and control center is connected to each pump skid and high-voltage VFD electric drive system through a ring redundant communication network, and uses the pre-calculated multi-pump displacement compensation control method as described in any one of claims 1 to 4 to perform displacement compensation. The command and control center and all high-voltage VFD drive equipment use hard-wired emergency stop control.

[0012] Preferably, it includes a data acquisition unit, a data preprocessing unit, a data processing unit, and a dynamic compensation execution unit; The data acquisition unit is responsible for collecting real-time discharge data from the relevant pump skids; The data preprocessing unit calculates the online reserve margin under different load levels of the system based on the load level set in the system. The data processing unit calculates the displacement of each pump skid at different load levels based on the pre-calculated multi-pump displacement compensation control method and executes the compensation command.

[0013] An operation method for a multi-pump displacement compensation control system based on pre-calculation includes the following steps: S1) The system performs a power-on self-test to confirm that the functions of each pump skid, control system, high-voltage VFD electric drive system and command and dispatch control center are normal. S2) Test the emergency stop function and the reliability of the ring redundant communication network; S3) Configure system parameters, including the load level, rated displacement, maximum displacement, minimum number of pump skids online, and total displacement required for each operation stage; S4) The pre-calculated multi-pump displacement compensation control method is activated, and the system enters fully automatic operation mode.

[0014] Preferably, in step S2), when testing the emergency stop function, the command and dispatch control center sends an emergency stop signal to each high-voltage VFD electric drive system, and manually jogs each pump skid to test and confirm that the emergency stop of the pump skid is effective. Under local control mode, the equipment is manually started and stopped, and the operation is normal.

[0015] Preferably, in step S2), when testing the reliability of the ring redundant communication network, the test equipment is jogged at the command and dispatch control center and the equipment can start normally. One end of the ring redundant communication network is removed, and the test equipment is jogged again and the equipment can start normally. The removed network is restored, and the other end of the ring redundant communication network is removed. The equipment is jogged again at the command and dispatch control center and the equipment can still start.

[0016] Compared with the prior art, the present invention has the following advantages: 1. By pre-calculating displacement compensation schemes under various fault scenarios and automatically executing them in milliseconds when the pump skid stops or the displacement deviation exceeds the limit, the displacement and pressure fluctuations during construction are effectively suppressed, ensuring that fracturing operations are strictly carried out according to geological design parameters, and significantly improving the production enhancement effect of oil and gas wells; 2. Introduce a load level management mechanism to dynamically allocate compensation loads based on the performance differences of pump skids, prioritize the use of high-performance equipment, and avoid overloading of old or inefficient pump skids, so as to fully utilize the potential of each piece of equipment and extend the service life of the overall equipment. 3. There is no need to maintain a large number of online hot standby pump skids for a long time. Offline standby machines are only activated when the backup is expected to be insufficient. This reduces the redundant configuration of high-pressure VFD and pump skids, saving tens of millions of yuan in fixed investment per well site. At the same time, it significantly reduces idle energy consumption and achieves energy-saving and low-carbon operation. 4. By adopting a multi-round step-by-step compensation algorithm, combined with the high speed accuracy of variable frequency closed-loop control, the total displacement error of the stable control system is far superior to that of traditional manual adjustment or simple feedback control. 5. A ring-redundant communication network is adopted to ensure the reliability of data transmission. Emergency stop signals are directly connected via hard wires to ensure rapid power cut-off in emergency situations, meeting the stringent safety and reliability requirements of oil fracturing operations. Detailed Implementation

[0017] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," indicating orientation or positional relationships, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0019] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0020] A multi-pump displacement compensation control method based on pre-calculation includes the following steps: S1) Configure the load level, rated displacement and maximum displacement of each pump skid. The load level I includes level 1, level 2, ..., level i, where level 1 is the lowest, indicating the weakest performance of the pump skid, and level i is the highest, indicating the best performance. S2) Calculate the online reserve margin A=P e -P x-set -P avg-line In the formula, P e P represents the total rated displacement of the online pump skid. x-set To design the required total displacement for operation phase x, P avg-line The average displacement of a single pump skid in the online system is given. If A > 0, proceed to step S3. If A ≤ 0, meaning the online backup capacity is insufficient, the system alarms and the command center activates the backup pump skid. S3) Perform displacement compensation pre-calculation; S4) Load level I=1; S5) Calculate the compensation base B under the current load level I. I =(P x-set -P online ) / N I In the formula, P online N represents the total real-time discharge of the online pump skid. I The total number of online pump skids shall not be less than the current load level I; S6) Obtain the calculated displacement P of the online pump skid at the current load level. n-c =P n +B I Pn This represents the real-time discharge capacity of the nth pump skid. S7) If P n-c ≤P n-max P n-max If the maximum displacement is set for the nth pump skid, proceed to step S8). n-c >P n-max (I = I + 1, return to step S5) until P is satisfied. n-c ≤P n-max If the load level is i, it still cannot satisfy P. n-c ≤P n-max If the hot standby pump capacity is insufficient, the system will alarm and the command center will activate the standby pump skid. S8) Calculate the calculated displacement P of all online pump skids. n-c =P n +B I When a fault occurs, compensation is performed.

[0021] After the compensation is performed, calculate the compensation error K=|P online -P x-set | / P x-set If K≤M, where M is the compensation accuracy (in this embodiment, a compensation accuracy less than or equal to 0.5% is considered normal), then the error accuracy compensation L = (P... online -P k-set ) / N I For each pump skid, error accuracy compensation L is performed.

[0022] In addition, in this embodiment, when the number of pump skids online is less than the minimum number of online pump skids, the system alarms and the command center activates the backup pump skids.

[0023] In this embodiment, offline 1, 2, 3 are calculated sequentially based on the number of online pump skids. The compensation amount is calculated up to the minimum number of online pump skids, and the results are marked on the system. When the system conditions are triggered, the system directly compensates with the displacement based on the calculated results.

[0024] This embodiment also relates to a pre-calculated multi-pump displacement compensation control system, including: several pump skids, each equipped with an independent control system, and liquid flowing from the low-pressure manifold through the pump skid and then into the high-pressure manifold to enter the formation. The high-voltage VFD electric drive system adopts a "one-to-two" structure, with a single high-voltage VFD electric drive system driving two pump skids. The command and dispatch control center is responsible for controlling and monitoring all power pump skids at the well site, monitoring and controlling relevant process parameters and curves during construction, and ensuring that the construction is consistent with the design of the geological research institute. To ensure the accuracy and reliability of control, the command and dispatch control center is connected to each pump skid and high-voltage VFD electric drive system through a ring redundant communication network, and adopts a multi-pump displacement compensation control method based on pre-calculation for displacement compensation. The command and control center and all high-voltage VFD drive equipment use hard-wired emergency stop control to ensure reliability in emergency situations.

[0025] In addition, this system includes a data acquisition unit, a data preprocessing unit, a data processing unit, and a dynamic compensation execution unit; The data acquisition unit is responsible for collecting real-time discharge data from the relevant pump skids; The data preprocessing unit calculates the online reserve margin under different load levels of the system based on the load level set in the system. The data processing unit calculates the displacement of each pump skid at different load levels based on the pre-calculated multi-pump displacement compensation control method and executes the compensation command.

[0026] The operation method of this system includes the following steps: S1) The system performs a power-on self-test to confirm that the functions of each pump skid, control system, high-voltage VFD electric drive system and command and dispatch control center are normal. S2) Test the emergency stop function and the reliability of the ring redundant communication network; S3) Configure system parameters, including the load level, rated displacement, maximum displacement, minimum number of online pump skids for each pump skid, and the total displacement required for each operation stage, the single pump skid displacement for different operation stages, and the total displacement of the entire well site for different operation stages. The system supports one-click import of data in tabular format for different operation stages, and the operation stages can be automatically executed based on the data imported for different operation stages. S4) The pre-calculated multi-pump displacement compensation control method is activated, and the system enters the fully automatic operation mode. Fully automatic operation means that the operator can start and stop the entire process equipment with one click. The equipment starts in the order of equipment load level from high to low. The equipment displacement adjustment is carried out in the order of equipment load level from high to low according to the design algorithm.

[0027] Specifically, in step S2), when testing the emergency stop function, the command and dispatch control center sends emergency stop signals to each high-voltage VFD electric drive system. Each pump skid is manually jogged to confirm the pump skid emergency stop is effective. Under local control mode, the equipment is manually started and stopped, and operation is normal. When testing the reliability of the ring redundant communication network, the equipment is jogged at the command and dispatch control center. The equipment starts normally. One end of the ring redundant communication network is removed, and the equipment is jogged again; the equipment starts normally. The removed network is restored, and the other end of the ring redundant communication network is removed. The equipment is jogged again at the command and dispatch control center, and the equipment still starts normally.

[0028] This system fully considers the operating conditions of equipment at the construction site. During fracturing operations, there are inevitable differences in the age and performance of equipment at the construction site, and the maximum displacement of each pump skid is also different. By designing a load level classification function, it ensures that the pump skids at the site can perform at their maximum efficiency according to their own operating conditions, and also ensures that the relevant pump skids are not overloaded during the system adjustment process, effectively guaranteeing the stability and reliability of the system adjustment process.

[0029] Meanwhile, this method is based on the minimum process displacement requirement of the pressure field pump skids. The design logic involves pre-calculating displacement compensation. During construction, operators preset system parameters according to the construction process, such as the maximum displacement, rated displacement, pump skid load level, and minimum number of online pump skids. The system will then calculate the offline 1, 2, 3, and 4 skids sequentially based on the number of online pump skids. The compensation amount under the minimum number of pump skids in online operation is calculated, and the system is marked. When the system condition is triggered, the system directly compensates with the displacement of the calculated result.

[0030] This method employs a hierarchical and step-by-step calculation approach with multiple rounds of polling. The application of this control algorithm not only fully considers the state characteristics of the equipment but also ensures that the on-site compensation is most rationally allocated to the online pump skid based on the pump skid's condition, which is highly beneficial for system stability and extending the service life of the equipment.

[0031] This invention relates to a pre-calculated multi-pump displacement compensation control method and system. By pre-calculating displacement compensation schemes under various fault scenarios and automatically executing them within milliseconds when pump skids stop or displacement deviations exceed limits, it effectively suppresses displacement and pressure fluctuations during construction, ensuring that fracturing operations are strictly performed according to geological design parameters, and significantly improving oil and gas well production. It also introduces a load level management mechanism, dynamically allocating compensation loads based on pump skid performance differences, prioritizing high-performance equipment, and avoiding overload operation of old or inefficient pump skids. This fully utilizes the potential of each piece of equipment and extends the overall equipment lifespan. Furthermore, it eliminates the need for long-term maintenance of large quantities of pumps. The online standby pump skid only activates the offline standby unit when insufficient backup is anticipated, reducing redundant configurations of high-pressure VFDs and pump skids. This can save tens of millions of dollars in fixed investment per well site, while significantly reducing idle energy consumption and achieving energy-saving and low-carbon operation. Employing a multi-round step-by-step compensation algorithm combined with the high speed accuracy of variable frequency closed-loop control, it stabilizes the total displacement error of the control system, far superior to traditional manual adjustment or simple feedback control. A ring-based redundant communication network ensures reliable data transmission, and emergency stop signals are directly connected via hardwired connections to ensure rapid power cut-off in emergencies, meeting the stringent safety and reliability requirements of oil fracturing operations.

[0032] It should be noted that the above description of the technical solutions is exemplary, and this specification may be embodied in different forms and should not be construed as limiting it to the technical solutions set forth herein. Rather, providing these descriptions will ensure that the disclosure of this invention is thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Furthermore, the technical solutions of this invention are defined only by the scope of the claims.

[0033] The aspects disclosed in this specification and claims are merely examples, and therefore, this specification and claims are not limited to the details shown. In the foregoing description, detailed descriptions of relevant known functions or configurations have been omitted where it would unnecessarily obscure the focus of this specification and claims.

[0034] When using the terms “comprising,” “having,” and “including” as described in this specification, there may be another part or other part unless used, and the terms used are generally singular but may also be plural.

[0035] Finally, it should be noted that the above description is a further detailed explanation of the invention in conjunction with specific embodiments. It should not be considered that the specific implementation of the invention is limited to these descriptions. For those skilled in the art, any simple substitutions made without departing from the concept of the invention should be considered within the scope of protection of this invention. The above embodiments are merely representative examples of the invention. Obviously, the invention is not limited to the above embodiments and many variations are possible. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the invention should be considered within the scope of protection of this invention.

[0036] It should be noted that the above description of the technical solutions is exemplary, and this specification may be embodied in different forms and should not be construed as limiting it to the technical solutions set forth herein. Rather, providing these descriptions will ensure that the disclosure of this invention is thorough and complete, and will fully convey the scope of this specification to those skilled in the art. Furthermore, the technical solutions of this invention are defined only by the scope of the claims. Features of various embodiments of this invention may be combined or spliced ​​together in part or in whole, and may be implemented in various different configurations as will be fully understood by those skilled in the art. Embodiments of this invention may be implemented independently of each other or may be implemented together in an interdependent relationship.

[0037] For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention, and the above structures should all be considered to fall within the protection scope of the present invention.

Claims

1. A multi-pump displacement compensation control method based on pre-calculation, characterized in that: Includes the following steps: S1) Configure the load level, rated displacement and maximum displacement of each pump skid. The load level I includes level 1, level 2, ..., level i, where level 1 is the lowest, indicating the weakest performance of the pump skid, and level i is the highest, indicating the best performance. S2) Calculate the online reserve margin A=P e -P x-set -P avg-line In the formula, P e P represents the total rated displacement of the online pump skid. x-set To design the required total displacement for operation phase x, P avg-line The average displacement of a single pump skid in the online system is given. If A > 0, proceed to step S3. If A ≤ 0, meaning the online backup capacity is insufficient, the system alarms and the command center activates the backup pump skid. S3) Perform displacement compensation pre-calculation; S4) Load level I=1; S5) Calculate the compensation base B under the current load level I. I =(P x-set -P online ) / N I In the formula, P online N represents the total real-time discharge of the online pump skid. I The total number of online pump skids shall not be less than the current load level I; S6) Obtain the calculated displacement P of the online pump skid at the current load level. n-c =P n +B I P n This represents the real-time discharge capacity of the nth pump skid. S7) If P n-c ≤P n-max P n-max If the maximum displacement is set for the nth pump skid, proceed to step S8). n-c >P n-max (I = I + 1, return to step S5) until P is satisfied. n-c ≤P n-max If the load level is i, it still cannot satisfy P. n-c ≤P n-max If the hot standby pump capacity is insufficient, the system will alarm and the command center will activate the standby pump skid. S8) Calculate the calculated displacement P of all online pump skids. n-c =P n +B I When a fault occurs, compensation is performed.

2. The multi-pump displacement compensation control method based on pre-calculation as described in claim 1, characterized in that: After the compensation is performed, calculate the compensation error K=|P online -P x-set | / P x-set If K≤M, where M is the compensation accuracy, it is considered normal. If K>M, then the error accuracy compensation L=(P) is calculated. online -P k-set ) / N I For each pump skid, error accuracy compensation L is performed.

3. The multi-pump displacement compensation control method based on pre-calculation as described in claim 2, characterized in that: The compensation accuracy is less than or equal to 0.5%.

4. The multi-pump displacement compensation control method based on pre-calculation as described in claim 1, characterized in that: When the number of pump skids in operation is less than the minimum number of pump skids in operation, the system will alarm and the command center will activate the backup pump skids.

5. The multi-pump displacement compensation control method based on pre-calculation as described in claim 1, characterized in that: Based on the number of online pump skids, calculate offline 1, 2, 3 successively. The compensation amount is calculated up to the minimum number of online pump skids, and the results are marked on the system. When the system conditions are triggered, the system directly compensates with the displacement based on the calculated results.

6. A multi-pump displacement compensation control system based on pre-calculation, characterized in that: include: Several pump skids, each equipped with an independent control system; The high-voltage VFD electric drive system adopts a "one-to-two" structure, with a single high-voltage VFD electric drive system driving two pump skids. The command and control center is connected to each pump skid and high-voltage VFD electric drive system through a ring redundant communication network, and uses the pre-calculated multi-pump displacement compensation control method as described in any one of claims 1 to 4 to perform displacement compensation. The command and control center and all high-voltage VFD drive equipment use hard-wired emergency stop control.

7. The multi-pump displacement compensation control system based on pre-calculation as described in claim 6, characterized in that: It includes a data acquisition unit, a data preprocessing unit, a data processing unit, and a dynamic compensation execution unit; The data acquisition unit is responsible for collecting real-time discharge data from the relevant pump skids; The data preprocessing unit calculates the online reserve margin under different load levels of the system based on the load level set in the system. The data processing unit calculates the displacement of each pump skid at different load levels based on the pre-calculated multi-pump displacement compensation control method and executes the compensation command.

8. An operation method for a multi-pump displacement compensation control system based on pre-calculation as described in claim 6, characterized in that: Includes the following steps: S1) The system performs a power-on self-test to confirm that the functions of each pump skid, control system, high-voltage VFD electric drive system and command and dispatch control center are normal. S2) Test the emergency stop function and the reliability of the ring redundant communication network; S3) Configure system parameters, including the load level, rated displacement, maximum displacement, minimum number of pump skids online, and total displacement required for each operation stage; S4) The pre-calculated multi-pump displacement compensation control method is activated, and the system enters fully automatic operation mode.

9. The operation method of the multi-pump displacement compensation control system based on pre-calculation as described in claim 8, characterized in that: In step S2), when testing the emergency stop function, the command and dispatch control center sends emergency stop signals to each high-voltage VFD electric drive system. Each pump skid is manually jogged to test and confirm that the emergency stop of the pump skid is effective. Under local control mode, the equipment is manually started and stopped, and the operation is normal.

10. The operation method of the multi-pump displacement compensation control system based on pre-calculation as described in claim 8, characterized in that: In step S2), when testing the reliability of the ring redundant communication network, the test equipment is jogged at the command and dispatch control center. The equipment can start normally. One end of the ring redundant communication network is removed, and the test equipment is jogged again. The equipment can start normally. The removed network is restored, and the other end of the ring redundant communication network is removed. The equipment is jogged again at the command and dispatch control center. The equipment can still start.