Grid-related Data Analysis Projects
Grid-related Data Analysis Projects
Nowadays, in response to the booming use of renewable energy, smart power generation has played an important role. TPC is actively seeking various test fields to develop a new generation of smart power generation, including Real-Time Damage Monitoring System (RtDMS) for Unit 9 of Taichung Power, condition monitoring and diagnostic system for HV motors of Taichung Power Plant, etc. The more intelligent power generation applications we use, the better power service we can provide.
2. Real-Time Damage Monitoring System
In the past, Taichung Power Plant experienced several boiler tube breakage accidents, which caused the power supply system in a critical situation. Consequently, we built the Real-Time Damage Monitoring System (RtDMS) for Unit 9 of Taichung Power Plant. With this pilot project, we provide an innovative approach which achieves predictive maintenance furnace to smart power generation.
2-3 Verify the accuracy of the RtDMS
During the overhaul of Unit 9 of Taichung Power plant, the results of the furnace tube damage detection has been inspected according to the location of the damage on the RtDMS to verify the accuracy of it.
Supervisory control and data acquisition(SCADA) have already been used for the main generator and auxiliary machinery systems in most power plants. SCADA collects operational data and programmable logic controls operational information as the foundation of automated operations and management. However, current monitoring capability is unable to provide fault detection and diagnosis of auxiliary machinery and equipment in power plants. We build a condition monitoring and diagnostic system for high-voltage motors. The condition monitoring and diagnostic system not only improves the reliability and the efficiency of the auxiliary equipment, but also greatly reduces the probability of the operation failure. In other words, power plant safety and power supply reliability can both be increased and improved.
1. Condition monitoring and diagnostic system for HV motors
Key Feature/ Function：
2. Data processing and analyzing
The kernel technology of the condition monitoring and diagnostic system is data processing and analysis which includes two parts, condition monitoring and fault diagnosis analysis.
The motor vibration is taken as the basis of the motors status in the condition monitoring system. The variation of current and the temperature of bearing are taken as references. When condition monitoring system receives excessive vibration, overload, or bearing temperature is too high, the system will reveal abnormal operation status. In terms of index selection, if different phases exist in the same index, the maximum value will be selected as the judgment basis.
The threshold value of the motor status index is set up according to international standards, the same as machine references and potential fault predictions. Among the electrical index and the vibration index, the thresholds are set up according to ISO 10816-3, NEMA MG1 and VDI 2056 international standards. There are four categories of motor status based on fuzzy inference rules: Good, Normal, Warning and Danger.
When the motor status is determined as “good”, HV motors will continue operating. When the motor status is determined as “normal”, fault diagnosis analysis will be executed. When the motor status is determined as “warning”, the motor failure will be revealed for repair in advance. When the motor status is determined as “danger”, alarms will be given to stop motors immediately to avoid further serious consequences.
Fault Diagnosis Analysis：
Fault diagnosis and analysis module is also based on fuzzy inference rules according to the mixture of vibration index and electrical index. Because the diagnosis indexes of a fault do not necessarily only include currently selected indexes shown on the left-hand side of the graph below, the diagnosis indexes might increase or decrease according to operation experience or the latest research. Consequently, the input indexes of the fault diagnosis and analysis module could be changed.
The vibration index and the electrical index have their own pros and cons. The mixture of the vibration index and the electrical index can improve the diagnosis reliability.
The architecture of the fault diagnosis analysis is based on the data measurement of an experimental motor (2HP LV motor) in a laboratory. The defect modes of the motor are stator short circuit, rotor broken bar, bearing damage, and misalignment. There are some structural differences between the experimental motor and the actual motor, especially in the bearing (oil-film bearing and ball bearing). In the future, an actual motor data measurement will be our main task.
3. Achievements and Prospects
The condition monitoring and diagnostic system is currently applied to 9 high-voltage motors of No. 5 unit in Taichung power plant, which provides a preliminary solution of condition monitoring and fault diagnosis. We plan to expand the experiment field to other units in Taichung power plant, or even other power plants. We will continue collecting and analyzing operational data on our Enterprise-level Big Data Platform and selecting kernel index to improve operations and maintenance strategies.
To enhance high-voltage motor operation reliability and fault diagnosis accuracy, our improvement plan is described below.
The statute stipulates that renewable energy sold greater or equal to 1000kW must return power generation information to the Taipower dispatching control center. Most solar photovoltaic power generation information is not returned to the dispatching center. As the end of December 2020, the total system installation solar photovoltaic capacity was about 5.5GW. In order to accurately grasp the instantaneous power generation of private solar photovoltaic power plants, Taipower sets up a Green Energy Estimate Monitor System (GEMS). The GEMS’s model uses the monitored power plant as the basis to estimate the power generation of neighboring unmonitored power plants. The GEMS will count the entire solar photovoltaic power generation in Taiwan. The GEMS is also combined the forecast of renewable energy power generation, with the current and understanding of the future renewable energy power generation situation, to dispatch traditional units and pumped storage units to cope with the duck curve caused by solar power generation.
1. The building of IEC 61850
At present, nearly 90% of the substation automation monitoring architecture adopt remote terminal units (RTUs), and most of the power meters, IEDs and RTUs use communication protocol DNP3.0. The monitoring architecture of the other substations adopt Local SCADA and gateway. The communication protocols between the gateways and IEDs are different (Modbus, DNP, LON, Profibus, etc.). The main function of these two substation automation methods is updating the real-time operation information in substation to the control center for dispatching (vertical communication), while the information cannot be exchanged horizontally between substations.
The full name of the IEC 61850 standard is "Communication networks and systems for power utility automation." The latest version, Edition 2, is an internationally accepted power automation standard that conforms to the future development trend of smart grids. Its main purpose is to provide the interoperability between different brands of IEDs.
In addition, the substation automation following the IEC 61850 monitoring architecture is also beneficial for the improvement of the reliability of power supply. This architecture provides a platform for horizontal communication (GOOSE) of automated equipment in the substation, enabling various equipment that enables to complete the application scenario of protection and operation in power system.
2. GOOSE Application of Simultaneous Accidents between Two Feeder Lines in compliant with IEC61850 Substation
The application of smart grids in the field of power transmission and transformation is mainly on the construction of substation automation based on the internationally accepted IEC 61850 standard. Intelligent electronic devices (IED) are the basic elements of digital automation substations, providing the protection, measurement, control and communication functions required by the system, and the GOOSE function which transmit events fast is used to transmit important instantaneous command signals between multiple IEDs. For this reason, the digital network communication is the substitute for the hard-wired control loop between traditional devices to achieve IEDs interoperability. In order to solve the problem of protection coordination difficulty caused by the simultaneous failure of the common feeders, which caused cross-zone tripping, the GOOSE information can be used to detect the IED trip protection logic to speed up feeder tripping, which strengthen the protection coordination between upstream IEDs and downstream IEDs, speed up the IED tripping on fault feeder to isolate the fault and reduce the scope of power failure.
Taking the 11.95kV BUS devices in the following figure as an example, there are MCB, CB1, CB2, CB3, and CB4, five circuit breakers. Among them, the CB1, CB2, CB3, and CB4 are feeder circuit breakers, and their IEDs planning GOOSE command accelerates CB tripping.
FD1_PKP=51P_PKP OR 51G_PKP
C. Benefit analysis
When more than two feeders have fault occurred at the same time, we accelerate the accidental feeder trip to avoid the action of the main circuit breaker, reducing the scope of power outages and improve the efficiency of power supply.
In 2014, our company developed and built an online query system for circuit breaker operating time. The operating time information of circuit breaker is recorded by the monitoring system of the dispatching center, which is used to establish a database of operating time data, and the status of circuit breaker can be effectively found through webpage. Substation is the main core of power grid, while building smart substation is an important process to make the grid smarter. In order to improve the quality of power supply meanwhile elevate the power system’s reliability and stability, substation automation and information digitalization are main task that we need to rely. By expanding the concept, Circuit Breaker Operating Time Online Query System will make a great improve on smart grid.
In response to current smart grid trend, our company also introduces the concept of Artificial Intelligence. By building a big data analysis model and analyzing the characteristics of the circuit breaker operating time, we can predict the normal circuit breaker operating time, and filters out a list of high-risk circuit breakers regularly sent to local colleagues. With the help of this warning, local colleagues can arrange maintenance, reaching preventive maintenance, reducing the possibility of power outages, and make the public feel that power supply is stable.
The system not only can reach preventive maintenance, but also makes the maintenance mode transfer from Time-based Maintenance (TBM) to Condition-based Maintenance (CBM). Related information can provide reference for decision-making in asset management and risk management as well.
Base on power supply dispatch’s substation maintenance manual, TPRI’s oil test will be done every year unless fault or abnormal situation of transformer happens. It is impossible to know the internal fault situation of the transformer in advance if we cannot obtain the gas content of the oil in the transformer and the operating status of the equipment timely. Current DGA(Dissolved gas analysis, DGA) shows the total amount of gas, it is hard to know exactly the amount of each gas, and the high number of abnormalities and expensive maintenance makes it not economical.
To ensure operation safety and achieve preventive maintenance, Taipower planned to install DGA for power supply units and replace the existing combustible gas detection device from the total type to the component type. It can obtain the content of gas components (H2, CO, water content) in the oil and alarm information, and judge the health of the internal operation of the transformer through each gas trend chart as the basis for CBM. It is expected that the effectiveness of the staff can be increase, equipment failure and blackout time can be decrease and ensure stable power supply.
Besides DGA, planning of existing transformer oil gas monitoring, transformer equipment asset management, and artificial intelligence AI applied to the transformer operation and maintenance strategy expert system for horizontal information integration and database interface to further master the transformer operation situation. If the abnormal situation of transformer is analyzed correctly, power outage maintenance can be arranged in time to avoid unforeseen power outages caused by accident.
The positioning function of the digital relay is used on fault location system on transmission line. The fault ranging system platform calculates automatically to revise the fault ranging while the line fault is occurred. The calculated results can be sent directly to the newsletter. Allowing specific personnel to obtain fault data in real time to facilitate field colleagues to find the actual location of the line fault. Meanwhile, with the combination of geographic data, the coordinate positioning is simultaneously displayed on the e- map, and the information of the fault zone is imaged. It is convenient for inspectors to quickly find the fault point and improve inspection efficiency on transmission line.
Through the ranging of the digital relay, the distance measured by the two-terminal distance relay must be input at first, then calculate with the total line length obtained from lightning fault information system. The correction method of the fault location is as follows:
When TOTAL：Total fault indication distances at both ends of the line (km)
FA：A-end distance after correction (km)
FB：B-end distance after correction (km)
OA：A-end original fault indication distance (km)
OB：B-end original fault indication distance (km)
DST=The total length of transmission line(km)
By inputting fault data to the lightning fault information system and combining geographic data with e- maps to indicate fault zone, the maintenance personnel are notified to find the fault location as soon as possible. In this way, it can improve the efficiency of maintenance inspection and troubleshooting and shortens the outage time.
In order to develop the renewable energy and reduce the impact of thermal power generating units on air quality, Peng-hu is the first area of Taiwan to promote low-carbon demonstration sites. It hopes to combine green energy, electric vehicles and solar water heaters to become a green energy tourism demonstration island that uses 100% renewable energy.
With the increasing proportion of wind power generation, The excess power in Peng-hu can be transmitted to Taiwan's main island in the future to achieve system stability and fully renewable energy usage. Taiwan's main island can also supply power when the wind power in Peng-hu is insufficient. Therefore, the concept of power transmission between Taiwan and Peng-hu promoted the development of Tai-Peng Cable nowadays.
Tai-Peng Cable is a submarine cable along Tai-zi village at Yun-lin to Hu-shi country at Peng-hu. Since we cannot prevent accidents as general inspection, we use the information of ships sailing in the Taiwan Strait to develop a Tai-Peng cable early warning and maintenance platform, which actively discover ships and collect navigational conditions to notify and drive away the ships may anchor in advance to reduce the risk of anchoring submarine cables.
2. Actual benefits of platform
A. Prevent ship anchor striking the cable instant monitoring system: Because of the construction cost of the Tai-Peng cable is huge. Passive detection of accidents is a non-permanent maintenance method. To prevent the anchor striking the cable, the instant monitoring system is a new way for power supply units to maintain the cable.
B. Not missing ships anchoring at high risk: Monitoring and maintenance personnel can set up relevant early warning mechanisms based on the tonnage and speed of the ships, and warn against the harmful ships at specific areas to reduce the risk of the anchor striking the cable.
C. Passive warning change to active message in advance: To implement the spirit of proactive maintenance and propaganda, and immediately informing the ships that have been identified as hazardous to be far away from the submarine cables by proactive message, preventing the ships from anchoring the cable.
D. Build the database without missing data: Recording the ships and establishing special observation lists for abnormal ships that have been traveling in the surveillance area. In addition to query the ship's capital and historical trajectory for maintenance personnel, it can also analyze the ship's type and navigation mode with big data.
E. Multi-system integration platform: In addition to the submarine cable operation status and the optical fiber detection system introduced, we also implement monitoring the health status of submarine cables to ensure the stability of power supply, and regular reviewing and correcting the ship anchor alarm parameters. Considering the displacement of submarine cable paths caused by ocean currents, we regular survey and correct the warning areas range to effectively use the early warning function.
F. The responsibility for power supply units: The Tai-Peng Cable take the heavy responsibility of green energy integration, and it becomes a new challenge for power supply maintenance department. We will continue to accumulate the experience of submarine cables to prevent anchoring and implement the maintenance works.
3. The benefit of platform after evaluating
A. Effectively reduce the power system failure occurrence (System Average Interruption Frequency Index, SAIFI)：The platform system proactively handles high-risk ships, and issues an alert in advance, asking the ships to leave the alert range of the Tai-Peng cable, which can effectively prevent the occurrence of damage to the marine cable from the ship anchoring, thereby improving the reliability of power supply and greatly reducing the probability of outages.
B. Reduce the cost of submarine cables(Key Performance Indicators, KPI)：The cost of repairing submarine cable is about 15 million, and the daily generating cost of Jian-shan standby power unit was about 3.36 million. If N-1 accident occurs in the Tai-Peng submarine cable, it will be equivalent to 100 million dollars per month during the restoration period. Moreover, the restorage project cannot be completed in a short time because of weather condition, ocean currents, and special submarine cable-delayed flights; therefore, the early warning and maintenance platform system can help us to save at least about 400 million dollars.
4. Future improvement
A. Detecting the position and depth of the submarine cable through GPS every three years and confirming whether the submarine cable is damaged, displaced, etc., and updating the warning range and navigation map of the submarine cable to ensure the safety of the submarine cable.
B. The current warning messages of this system sent to each ship are through the "Ship Identification System" from the Maritime and Port Bureau. In order to strengthen the autonomous functionality of this platform, the feasibility of building a system by ourselves has been evaluated.
Taiwan is located on the Pacific Rim earthquake belt and the path of typhoons in summer. Therefore, natural disasters such as earthquakes and typhoons often occur. The mountain slopes are steep with rapid currents and the geology is fragile, causing natural disasters such as slope collapse, earth and rock flows, endanger the safety of transmission towers in mountainous areas.In response to the problem of power supply stability due to the sliding of tower foundation slopes by the extreme weather in recent years, the project applies fixed-type tilt meter and other slope monitoring instruments with real-time dynamic positioning system to 5 towers, including 345 kV Daguan, Mingtan - Fenglin line , #52, #68, #163, and 161 kV Fenglin Hualien Line # 76, # 77, for the construction of the tower-based slope disaster prevention early warning system and the application of real-time dynamic positioning assessment research. This project is to monitor target towers with the real-time kinematic, structural monitoring system, tower-based monitoring system and environmental monitoring system. The back-end management system provides an early warning function, and the warning signals of the monitoring equipment are displayed with lights in the tower-based monitoring management platform, so that tower maintenance managers access to cloud data through the user monitoring interface, and immediately grasp the status of the monitoring tower.
The basic dynamic intelligent monitoring system of the tower includes four systems: power system, sensing system, communication system and data system analysis management. Taipower plan to use real-time kinematic, structure monitoring system, tower-based monitoring system and environmental monitoring system to formulate the sensing system for monitoring the target tower. The functions of each system are summarized as follows:
In addition, the sensing system require the power system to provide the power. This project uses the solar power generation system to supply the overall monitoring system power source, and establishes a stable power supply system, including lithium battery energy storage equipment, so that when the power is insufficient, the energy storage equipment can supply the power for communication at least 30 days. Monitoring data is transmitted through the communication system to the management platform. This project is evaluated to use reliable communication technology for the monitoring tower to the connection tower (with Taiwan power company OPGW Joint Box tower) such as LoRa, 4G... and build its communication system, and carry out the communication test of photoelectric conversion.
The data analysis management system is the processing center for all monitoring data. Taipower can get complete and long-term monitoring data, real-time monitoring of geodetic displacement, structural displacement, and water level observation, and analyze whether relevant real-time data exceeds the safety alert value. This system will provide an early warning after data is analyzed. The warning signal of the monitoring equipment is displayed on the tower-based monitoring and management platform, so that the field personnel can obtain cloud data through the user monitoring interface, and immediately grasp the status of the monitoring tower.
3. Projects objectives and benefits
The objective of this project is to establish a long-term monitoring system for the target tower, to grasp the structure of the tower and the situation and development of land shift, and to provide reference for the maintenance, power operation and disaster early warning. Accordingly, the project intends to carry out the construction of local power systems, communication systems, monitoring instruments, and the development of monitoring webpages for 5 monitoring towers, with the following objectives:
This project envisages the establishment of the basic dynamic intelligent monitoring system of the tower and achieves the following results.
In order to realize the smart transmission plan, this project investigate the method of increasing the transmission capacity. According to the power associations in the world, including the IEEE, JCS, and CIGRE, the relevant standards are formulated based on heat equation of conductor. The dynamic thermal rating (DTR) method is proposed to effectively increase the transmission capacity with real-time data. The project studied DTR according to the plan requirement. The contents before the first mid-term report have five points. 1. Compare and explore DTR and static thermal rating (STR). 2. Discuss DTR formula and parameter. 3. Collect relevant DRT research and application of foreign electric industry and manufacturers. 4. Design and Verify IoT technology introduced into high voltage system. 5.Design and verify DTR equipment.
This study is a practical application of DTR. In addition to data collection, performing high-voltage and high-current tests are also necessary on DTR equipment to test and prove the reliability and stability of the equipment, which is conducive to subsequent research in the line installation under the supervision of operators and equipment. This will help to understand the actual state of the line after capacity increase and accumulate the experience of using DTR to improve capacity operation. In the future, it can further modify the power dispatching and power transmission specification.
2. Content and method
A. Dynamic thermal rating equipment and small weather stations with wireless communication testing and verification
B. Application management platform program development
In order to realize the dynamic thermal rating monitoring, this plan will investigate the current application status of dynamic thermal rating or related equipment on the market in order to understand the relevant results of foreign dynamic thermal rating research as a reference for this research. The plan uses domestic existing dynamic thermal rating monitoring equipment, installed on Taipower's designated transmission line, and installs a small weather station to collect real-time weather information around the tower to collect real-time and accurate power line dynamic heat capacity information. Through big data and Application of artificial intelligence technology, analyze and discuss the prediction technology of dynamic heat capacity. At the same time, this plan also intends to build a dynamic heat capacity cloud application management platform to display the power line environment information and dynamic heat capacity information in real time to provide more information for maintenance personnel to judge the safety of power lines.