Figure 23 illustrates the installation locations of sensors as described in chapter 2.3. The layout has been simplified compared to the original. Air interfaces are connected to the readers via cables. Busbars are presented with three-phase approach. Auxiliary cabinet is included as switchgears are commonly equipped with multiple auxiliary devices. IntelliSAW readers and needed auxiliary components can be easily fitted in the auxiliary cabinet. Wiring diagram and necessary auxiliary components for reader are illustrated in Figure 24.
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Figure 23. Installation locations of IntelliSAW components
Figure 24. Wiring diagram of the reader (Intellisaw. 2016. IntelliSAW IRM-48 Reader Installation Manual)
37 2.5 Layout of the test system
In this thesis the IntelliSAW temperature monitoring system was tested in practice. Figure 25 shows a simplified layout of the HECON test switchgear that was used for the testing of the temperature monitoring system. Figure 25 indicates the location of the sensors in the test switchgear. The main switch is indicated in the figure on the top leftside of the switchgear and the supply cables will be connected from above to the main switch. The main switch is connected with the horizontal main busbar system. The outgoing MCCB is connected with the horizontal main busbar system with wires and the outgoing cables are connected from above.
Figure 25. Test HECON component locations
38 2.6 Part list of the test system
For the testing of the temperature monitoring system in the thesis the following IntelliSAW components were determined for the HECON test switchgear (Figure 25) and purchased.
The following parts were selected.
Sensors:
- 6 x LP-XX (Band 01- 06) Intellisaw Low Profile Temp Sensor - 6 x IS-XX (Band 07- 12) Intellisaw Standard Temp Sensor
Air interfaces:
- 4 x IA-MM-TMP-7 Intellisaw Air Interface Base Unit, Temp Only, Mag Mount, 7 m cable
Reader:
- 1 x IRM-48-T00 Intellisaw Remote Monitoring Unit, Temp Only
Auxiliary components in the tests were:
- 1 x Power Supply 230 VAC/24 VDC: Omron S8VK - S03024 - 1 x 2-pole C-curve 4 A MCB: Siemens 5SY4204-7
39 2.7 Monitoring system development
2.7.1 Introduction
IntelliSAW has its own hierarchy depending on how large the system is in question. The minimum number of required devices to view the temperature data is one reader. When air interfaces are added to the system the number of readers will also increase. Transferring data outside the IntelliSAW system depends on the external customer system and should be determined individually in each case. If a Modbus RTU is a suitable protocol for the customer, it can be easily transferred forward. In other cases, protocol change has to be done with a suitable gateway. The gateway can be installed into the switchgear or it can be located in another place depending on the customer architecture. In addition, an additional RTU unit could be installed into switchgear, from where the Modbus data can be sent and the RTU unit would be a part of the factory control system. Figure 26 presents an example of RTU principle with Siemens Simatic RTU, where different kinds of measurement data can be centralized and forwarded to the Simatic automation system. This is just an example of one manufacturer-based automation system, but some other manufacturer’s system could also be used.
Figure 26. Example principle of Siemens Simatic RTU (Siemens. 2021)
2.7.2 Topology of monitoring systems
Reader IRM-48 can send data of temperature values forward in Modbus RTU protocol. This data can be sent to control systems directly in the same protocol or the protocol can be transformed from the Modbus RTU to an another one with gateways (Figure 27). Gateway can
40 be installed into the switchgear auxiliary cabinet or the transformation can be executed in a different location if Modbus RTU RS-485 data is transferred via field cable.
Figure 27. Example Modbus RTU gateway connection to Modbus TCP Scada. (Lin, J. 2016)
When multiple readers are used, the units can be connected in parallel as presented in the Figure 28. Half-duplex RS485 shielded 3- wire twisted-pair cable is recommended to be used for data connections. When long stretches of cables are used, 120 ohm resistors must be used at the end of the termination to ensure correct resistance. If the bus length is under 20 meters, termination resistors may be omitted (Intellisaw. 2016. IntelliSAW IRM-48 Reader Installation Manual).
Figure 28. Diagram with multiple readers (Intellisaw. 2016. IntelliSAW IRM-48 Reader Installation Manual)
41 CAM-5 unit can be very helpful part of the system, if the number of readers is high. In such cases, multiple readers can be connected to a CAM-5, which could be connected further with Scada. CAM-5 units can also be connected in parallel. The topology is presented in Figure 29.
In conclusion, the CAM-5 units are additional components for the IntelliSAW system in cases, e.g., where the local door monitoring is required or in cases where the system is large and multiple readers are in use.
Figure 29. IntelliSAW CAM-5 system architecture (Intellisaw. 2020. IntelliSAW Monitoring Solutions Overview 2020)
2.7.3 Software setups with Modbus IP-addresses to view data
IntelliSAW Configuration Tool is a software, which is used to configure the system and to monitor and log temperature data. At configuration, the air interface ports and sensors are determined. IntelliSAW recommends not to install adjacent sensors under the same air interface for sensor identification. It is recommended to have one number skip in sensors under the air interface. In example, when using sensors 07, 08 and 09 for the air interface in the port 1 and sensors 10, 11 and 12 for the air interface in the port 2 is incorrect. Instead, sensors 07, 09 and 11 for the air interface in the port 1 and sensors 08, 10 and 12 for the air interface in the port 2 is correct.
42 In the sensor register edit, air interfaces for the four different ports must be selected. The correct sensor identification codes must be determined for each port. Identification code is the number of a band and a specific letter for each sensor. Identification codes are presented on the sensors.
Location of the sensors can also be also determined in the configuration. This helps to keep in mind, which sensor is in which location. Temperature data is read from the Modbus register.
Each sensor data in the Modbus register number can be seen from the temp sensor display. This info is also used, when data is transferred to external factory control system. Data is read from the register and it must be known, which sensor data is under which Modbus register number.
Figure 30 presents a temp sensor display, where the above-mentioned data are presented. In the first time all the sensors can be calibrated with the ambient temperature. Bars under each temperature display are presenting signals between the air interface and the sensor. Signal can be green, yellow or red, which are indicating ”good”, ”average” or ”bad” connection.
Figure 30. Temp Sensor Display
Modbus temp readings window presents a graph of temperatures in real time (Figure 31). This view presents temperatures similar to the temp sensor display, but it has a 30-minute horizontal time axis, so the last 30-minute data can be seen from the graph.
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Figure 31. Modbus Temp Readings
Both windows have ”Log data” button. With this function data can be recorded to a Excel file.
Temperatures of each sensor is written to excel in one row in every second with the date and the time stamp. Data log can be started and ended manually (Intellisaw. 2016. IntelliSAW Configuration Tool User Manual).
2.7.4 Conclusions and preliminary solutions
In every project the structure of the switchgear and data monitoring demands can vary.
However, some preliminary electrical schematics for typical solutions can be created in advance. It has been decided in the thesis that preliminary electrical schematics shall be created for four typical solutions. Each schematic shall consist of main components and wirings. These schematics can be easily modified to meet certain project demands. Also, different solutions can be combined with each other.
The four typical solutions are:
- Example 1: Single switchgear with one reader. Data monitoring on local laptop via USB (Appendix 3).
- Example 2: Single switchgear with one reader. Data monitoring for the customer through gateway (Appendix 4).
- Example 3: Example 3: Single switchgear with multiple readers. Data transmitted to the local Simatic CPU. Possibility to view data locally by HMI. Possibility to forward data to customer via Profinet (Appendix 5).
44 - Example 4: CAM-5 solution for multiple switchgears (Appendix 6).
For each solution wiring schematics, communication and device layouts are presented. Also, one part list is included, which includes all the required devices for the monitoring system (Appendix 7).
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3 TESTING OF SYSTEM
3.1 Test environment
Tests were performed in the test area of Harju Elekter Elektrotehnika, Keila Estonia. HECON LIGHT switchgear (Figure 33 – Figure 36) was used for the testing. The technical specifications of the switchgear are presented in Table 2.
Type HECON
Degree of protection enclosure IP44
Earthing system TN-S
Main busbars (L1, L2, L3) 2 × 30 × 10 Al
Main busbars (PE) 1 × 30 × 10 Al
Enclosure dimensions H × W × D [mm] 2100 + 100 × 750 × 265
Table 2. Technical specifications of HECON LIGHT test switchgear (Appendixt 4 & 5)
The main devices in the switchgear concerning the tests were the main switch, busbars and the outgoing MCCB. There were other devices in the switchgear, but those did not participate in the tests and are therefore not presented in this thesis.
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Figure 34. View of HECON test switchgear with doors open
Figure 33. View of HECON test switchgear with doors closed
Figure 36. MCCB 250 A in the HECON test switchgear, Siemens 3VA1225-4EF32
Figure 35. Main switch in the HECON test switchgear, Socomec Sirco 630 A
47 3.2 Testing method
The tests were performed with two different scenarios (test 1 and test 2). In both scenarios, the temperatures of the main switch’s incoming and outcoming connections were measured. IS type sensors were used for measuring the connection points of the main switch. The sensors were attached on the supply cable insulation as close as possible to the connection point. IS type sensors were installed under the bolts of the outgoing busbars of the main switch. The differences between the tests were that in the test 1 the main switch (MS) and the busbars were tested with the rated current (630 A). In the test 2 additional sensors were attached to the load side phase cables of the outgoing MCCB and sensors from the main busbars were reinstalled to the supply cables of the MCCB that were connected with the busbars. Then MCCB was loaded with the rated current of the MCCB (250 A) with load resistors.
In both tests, temperatures were analysed with three different monitoring systems. The IntelliSAW system, which was the system under testing and verification, was the main system.
The second system was Harju Elekter’s self-assembled temperature monitoring system with wired sensors. The wired sensors were installed in the same locations, where the wireless IntelliSAW sensors were installed. The third system was thermal imaging. Thermal images were taken at the end of each test from the same locations, where wired and wireless sensors were installed. The results from all the three monitoring systems were compared after the tests.
The wired sensor system was built from the following devices:
1. Thermocouples Z2-K-5M, Farnell 2. Amplifiers AD8495, Analog devices
3. PicoLog 1012 Data Logger and PP604 Terminal Board
Thermal camera that was used in the tests was Fluke Ti400.
48 Prior to the testing the expected busbar temperatures were evaluated. The busbars in the HECON test switchgear were sized according to the rated current of the switchgear, doubled 30 x 10 aluminium (for currents up to 780 A in free air, according to reference ABB. 2000).
The temperature rise of the busbars was designed 30 K. The ambient temperature according to the standard IEC 61439-1 must be considered 35 celsius degrees. The expected end busbar temperature would be 65 celsius degrees at the ambient temperature of 35 celsius degrees. The load current in the test 1 was 630 A, which is lower than 780 A, and the ambient temperature in the tests was appr. 22 not 35 celsius degrees, so the first expectations were that the busbar temperatures could be lower than 65 celsius degrees. However, in the tests all the air ventilations were blocked to meet the general IP44 protection degree for the switchgear. When natural air ventilation is not considered in the switchgear, the air temperature inside the switchgear should be higher, thus the busbars heat up more and the busbar temperatures would be higher than in free air. (ABB. 2000)
When both tests were performed, similar results from each temperature monitoring system were expected. Should the results be similar, it could be stated that the installation and configuration of the IntelliSAW system was successful and the system is working correctly and the data received is reliable. Should these three monitoring systems give all different data, further testing and analysis must be done, which of these three monitoring methods is accurate.
In both tests (test 1 and test 2), sensors were installed to monitor the main switch’s incoming and outgoing connections (Figure 37).
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Figure 37. Sensors installed on the connection points of the main switch
The HECON test switchgear was powered by Harju Elekter’s own supply cabinet. The supply cabinet is designed to carry out different temperature rise tests. The supply cabinet consists of a three-phase 17 kVA main transformer, which primary side can be supplied from the grid (400 VAC). The voltage of the secondary side of the voltage transformer is very low, only 3 x 1,5-3,5 VAC, but this enables high output current up to 4000 A (Figure 38).
Figure 38. Main transformer of the supply cabinet
The supply cabinet contains an adjustable autotransformer per each phase, where the primary voltage of the main transformer can be adjusted. With the autotransformers it is possible to adjust the output current of the supply cabinet. In the testing area, it is possible to test different switchgears either by short-circuiting the test switchgear’s main busbars with a copper busbar to load the switchgear without any loads (with the autotransformers it is possible to adjust the
50
“short-circuit current” to the rated current of the switchgear) or by loading outgoing circuits with loading resistors. The HECON test switchgear main busbars were short circuited (Figure 43) in the test 1 to load the switchgear with rated current of 630 A. Autotransformers can be seen in the Figure 39 just above the cable connection. The meters above the autotransformers display values of voltages and currents in the grid side.
Figure. 39 Supply cabinet
3.3 Software setup
Prior testing the auxiliary components of both monitoring systems were placed outside of the test switchgear. Author and the electrical engineer from As Harju Elekter Elektrotehnika supporting these tests were both analysing data throughout the testing. Figure 40 presents the test environment, where were two laptops, one for the wired system and one for the wireless Intellisaw system. Author was operating with the IntelliSAW system data.
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Figure 40. Test environment, data analysing
51 IntelliSAW system configuration was done successfully according to the manufacturer’s manual (Intellisaw 2016. IntelliSAW IntelliSAW Configuration Tool User Manual). Each sensor was found by the system and temperatures were corresponding to the ambient temperatures. Sensors were named by the locations, where those were installed (Figure 41).
Figure 41. Sensor data in temp sensor display before tests.
52 3.4 Test 1
In the test 1 the HECON test switchgear main busbars were short circuited (Figure 43) to load the switchgear with the rated current of 630 A. Figure 42 presents the principle diagram of the test 1. The same figure can be found from the appendices, Appendix 8.
Figure 42 Principle diagram of test 1
The HECON test switchgear had been designed in a way that it was easy and safe to short circuit the busbars. Figure 43 presents the short circuit bar that was used to connect the main busbars together.
Figure 43. Short circuit busbar
53 Figure 44 presents the installation of busbar sensors.
Figure 44. Test 1 register 424-426 sensors
In test 1 sensors were installed as shown in figures 37 and 44. In this test the outgoing MCCB feeder was not analysed and excessive sensors of registers 427 – 429 were used to measure the cable connections of the supply cabinet. One sensor was placed to measure the ambient temperature and the two sensors were installed to measure the phases of L1 and L2 of the cable connections of the supply cabinet (Figure 45).
Figure 45. Test 1 register 427-429 sensors
54 3.5 Test 2
In test 2 the outgoing MCCB feeder was loaded with rated current and the temperatures of the cable connections of the MCCB were measured. Figure 46 presents the principle diagram of test 2. The same figure can be found from the appendices, Appendix 9.
Figure 46. Principle diagram of test 2
In this test, the MCCB was loaded with load resistors and the short circuit busbar was not used.
The sensors presented in Figure 47 were installed to the outgoing cable connections of the outgoing MCCB.
Figure 47. Test 2 register 427-429 sensors
55 Sensors that were installed to the busbars in test 1 were re-installed to the cable connections of the cables between busbars and outgoing MCCB (Figure 48).
Figure 48. Test 2 register 424-426 sensors
In test 2 loading resistors were used (Figure 49). In the trolley there were four three-phase step-up transformers (that the currents in the loading resistors would be smaller compared with the currents in the switchgear) and three adjustable load resistors per each phase of the step-up transformer. In test 2, only one step-up transformer was needed to load the MCCB.
Figure 49. Loading resistors in test 2
56 Step-up transformer for the loading resistors had primary side voltage of 1.5 V and current 504 A and secondary side voltage of 400 V and current 1.9 A (Figure 50). The loading resistors for each phase were 165 ohms and 2 A (Figure 51).
Both the supply cabinet voltage and the resistance of load resistors were adjusted until the load in the MCCB circuit (Figure 52) was the same as the rated current of the MCCB 250 A.
Figure 52. Load current in the testing of the MCCB Figure 50. Step-up transformer Figure 51. Loading resistor
57 3.6 Test 1 results
Test 1 lasted three hours and 37 minutes. At first, 690 A load current was applied to speed up the temperature rise. When the temperatures had risen, the load current was set to the rated value of test HECON switchgear (630 A). In test 1, the main switch L1 wired sensor became loose after 50 minutes of testing. This can be seen in the test-1-wired-sensor report. Results are presented in Figure 53 (Appendix 8)
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Figure 53. Temperature rise graph of test 1 with wired sensors
IntelliSAW software was recording data to an Excel file during the tests. One row of temperature data was recorded in every second. Total of 13334 rows of temperature data was created to the Excel file when test 1 was completed. Figure 54 is presenting the graph from the received Excel data. The results are also presented in attachments, Appendix 10.
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Figure 54. Temperature rise graph of test 1 with IntelliSAW wireless sensors
In Table 3 are presented the steady state temperature values of the two temperature monitoring systems at the end of test 1. The first column indicates the measurement location. The second and the third columns present the steady state values of the wired sensor system and the wireless IntelliSAW sensor system. The differences between the results of the wired and IntelliSAW monitoring systems are brought out in the “Difference” columns (differences brought out in temperature K values and in percentage).
The temperature values of the main busbar are meeting the prior expectations described in chapter 3.2. In Table 2 the main busbar steady temperature is approximately 65 celsius degrees at the ambient temperature of 20 celsius degrees. Due to the blocked natural ventilation the main busbar temperature is higher than in the free air. This means that in the given
The temperature values of the main busbar are meeting the prior expectations described in chapter 3.2. In Table 2 the main busbar steady temperature is approximately 65 celsius degrees at the ambient temperature of 20 celsius degrees. Due to the blocked natural ventilation the main busbar temperature is higher than in the free air. This means that in the given