Figure 1.
Example of fault management in a medium-voltage (MV) network according to the logic selectivity paradigm. (a) Healthy conditions. (b) Fault between protection relay 2 (PR2) and PR3; transmission of blind signals. (c) Circuit breaker 2 (CB2) tripping, and transmission of the Trip signal to PR3. (d) CB3 tripping and transmission of the Close signal to Tie recloser (TR).
Figure 1.
Example of fault management in a medium-voltage (MV) network according to the logic selectivity paradigm. (a) Healthy conditions. (b) Fault between protection relay 2 (PR2) and PR3; transmission of blind signals. (c) Circuit breaker 2 (CB2) tripping, and transmission of the Trip signal to PR3. (d) CB3 tripping and transmission of the Close signal to Tie recloser (TR).
Figure 2.
Timing of the operations of PR1 and PR2 if a fault downstream of PR2 occurs.
Figure 2.
Timing of the operations of PR1 and PR2 if a fault downstream of PR2 occurs.
Figure 3.
Realized demonstrator for the experimental assessment of the system.
Figure 3.
Realized demonstrator for the experimental assessment of the system.
Figure 4.
Microcontroller and transceiver of the realized Long Range (LoRa) node.
Figure 4.
Microcontroller and transceiver of the realized Long Range (LoRa) node.
Figure 5.
State machine implemented on the microcontroller of a PR.
Figure 5.
State machine implemented on the microcontroller of a PR.
Figure 6.
Master-slave architecture that allows the PR (i) to simultaneously communicate with the upstream protection PR (i − 1) and the downstream protection PR (i + 1).
Figure 6.
Master-slave architecture that allows the PR (i) to simultaneously communicate with the upstream protection PR (i − 1) and the downstream protection PR (i + 1).
Figure 7.
Image of the realized PR prototype.
Figure 7.
Image of the realized PR prototype.
Figure 8.
Simultaneous transmission and reception of Blind messages between PRs on different channels.
Figure 8.
Simultaneous transmission and reception of Blind messages between PRs on different channels.
Figure 9.
Time–frequency diagram of a LoRa packet with a duration of 15.46 ms.
Figure 9.
Time–frequency diagram of a LoRa packet with a duration of 15.46 ms.
Figure 10.
Message exchange between protections during the fault 50.S3 between SR and PR1.
Figure 10.
Message exchange between protections during the fault 50.S3 between SR and PR1.
Figure 11.
Digital signals acquired during the fault 50.S3 between SR and PR1.
Figure 11.
Digital signals acquired during the fault 50.S3 between SR and PR1.
Figure 12.
Message exchange between protections during the fault 50.S3 between PR2 and PR3.
Figure 12.
Message exchange between protections during the fault 50.S3 between PR2 and PR3.
Figure 13.
Digital signals acquired during the fault 50.S3 between PR2 and PR3.
Figure 13.
Digital signals acquired during the fault 50.S3 between PR2 and PR3.
Figure 14.
Time–frequency diagram of a LoRa packet with a duration of 209.85 ms.
Figure 14.
Time–frequency diagram of a LoRa packet with a duration of 209.85 ms.
Figure 15.
Digital signals acquired during the fault 67N.S1 between SR and PR1.
Figure 15.
Digital signals acquired during the fault 67N.S1 between SR and PR1.
Figure 16.
Digital signals acquired during the fault 67N.S1 between PR2 and PR3.
Figure 16.
Digital signals acquired during the fault 67N.S1 between PR2 and PR3.
Figure 17.
Time–frequency diagram of a LoRa packet with a duration of 103.42 ms.
Figure 17.
Time–frequency diagram of a LoRa packet with a duration of 103.42 ms.
Figure 18.
Digital signals acquired during the fault 67N.S1 between SR and PR1, with a LoRa of 103.42 ms.
Figure 18.
Digital signals acquired during the fault 67N.S1 between SR and PR1, with a LoRa of 103.42 ms.
Figure 19.
Messages exchange during a fault 50.S3 between PR3 and TR.
Figure 19.
Messages exchange during a fault 50.S3 between PR3 and TR.
Figure 20.
Acquired Blind messages during a fault between PR3 and TR.
Figure 20.
Acquired Blind messages during a fault between PR3 and TR.
Figure 21.
Acquired digital signals during the fault 50.S3 between PR3 and TR.
Figure 21.
Acquired digital signals during the fault 50.S3 between PR3 and TR.
Figure 22.
Management of a fault between PR2 and PR3 when a connection problem occurs.
Figure 22.
Management of a fault between PR2 and PR3 when a connection problem occurs.
Table 1.
Devices involved in logic selectivity scenario.
Table 1.
Devices involved in logic selectivity scenario.
Acronym | Name | Function |
---|
CB | Circuit breaker | Device able to trip the circuit during a fault; its operations are controlled externally by the PR. |
PR | Protection relay | Device able to: (i) detect faults; (ii) control the respective CB; (iii) exchange messages with the other PRs. |
SB | Substation breaker | Breaker positioned in the primary substation. |
SR | Substation relay | Relay controlling the SB |
IB | Interconnection breaker | Breaker normally open that, if closed, connects the line to other distribution networks. |
TR | Tie recloser | Relay controlling the IB. |
Table 2.
Bit rate values depending on bandwidth (BW) and spreading factor (SF), with code rate (CR) = 1.
Table 2.
Bit rate values depending on bandwidth (BW) and spreading factor (SF), with code rate (CR) = 1.
| SF |
---|
BW | 7 | 8 | 9 | 10 | 11 | 12 |
---|
125 | 5468 | 3125 | 1757 | 977 | 537 | 292 |
250 | 10,937 | 6250 | 3515 | 1953 | 1074 | 585 |
500 | 21,875 | 12,500 | 7031 | 3906 | 2148 | 1171 |
Table 3.
Minimum signal-to-noise ratio (SNR) to be guaranteed for signal demodulation based on SF values.
Table 3.
Minimum signal-to-noise ratio (SNR) to be guaranteed for signal demodulation based on SF values.
SF | SNR Limit |
---|
7 | −7.5 |
8 | −10 |
9 | −12.5 |
10 | −15 |
11 | −17.5 |
12 | −20 |
Table 4.
Sensitivity values depending on BW and SF, with CR = 1.
Table 4.
Sensitivity values depending on BW and SF, with CR = 1.
BW (kHz) | SF | Sensitivity (dBm) |
---|
125 | 8 | −126 |
125 | 10 | −132 |
125 | 12 | −137 |
250 | 8 | −123 |
250 | 10 | −129 |
250 | 12 | −134 |
500 | 8 | −120 |
500 | 10 | −126 |
500 | 12 | −131 |
Table 5.
Values of (total transmission time of the LoRa packet), expressed in ms, versus BW and SF, with CR = 1, implicit header (IH = 1), CR = 1, cyclic redundancy check (CRC) = 1, payload of 10 bytes.
Table 5.
Values of (total transmission time of the LoRa packet), expressed in ms, versus BW and SF, with CR = 1, implicit header (IH = 1), CR = 1, cyclic redundancy check (CRC) = 1, payload of 10 bytes.
| SF |
---|
BW | 7 | 8 | 9 | 10 | 11 | 12 |
---|
150 | 37.12 | 64 | 128 | 256 | 430.08 | 860.16 |
250 | 18.56 | 32 | 64 | 128 | 215.04 | 430.08 |
500 | 9.28 | 16 | 32 | 64 | 107.52 | 215.04 |
Table 6.
Values of , in ms, versus BW and SF, with CR = 1. The red color indicates values of the table that are not feasible.
Table 6.
Values of , in ms, versus BW and SF, with CR = 1. The red color indicates values of the table that are not feasible.
| SF |
---|
BW | 7 | 8 | 9 | 10 | 11 | 12 |
---|
125 | 37.12 | 64 | 128 | 256 | 30.08 | 860.16 |
250 | 18.56 | 32 | 64 | 128 | 215.04 | 430.08 |
500 | 9.28 | 16 | 32 | 64 | 107.52 | 215.04 |
Table 7.
Receiver sensitivity in dB. The red color indicates values of the table that are not feasible.
Table 7.
Receiver sensitivity in dB. The red color indicates values of the table that are not feasible.
| SF |
---|
BW | 7 | 8 | 9 | 10 | 11 | 12 |
---|
125 | −123 | −126 | −129 | −132 | −134.5 | −137 |
250 | −120 | −123 | −126 | −129 | −131.5 | −134 |
500 | −117 | −120 | −123 | −126 | −128.5 | −131 |
Table 8.
Values of in ms depending on BW and SF, with CR = 1, CRC disabled, implicit header.
Table 8.
Values of in ms depending on BW and SF, with CR = 1, CRC disabled, implicit header.
| SF |
---|
BW | 7 | 8 | 9 | 10 | 11 | 12 |
---|
125 | 32 | 53.76 | 107.52 | 215.04 | 348.16 | 696.32 |
250 | 16 | 26.88 | 53.76 | 107.52 | 174.08 | 348.16 |
500 | 8 | 13.44 | 26.88 | 53.76 | 87.04 | 174.08 |
Table 9.
Times for fault clearing, detection, tripping, and blind waiting depending on the fault type.
Table 9.
Times for fault clearing, detection, tripping, and blind waiting depending on the fault type.
Fault Type | Fault Clearing [ms] | Fault Detection [ms] | Tripping [ms] | Blind Waiting [ms] |
---|
50.S3 Poly-phase short circuit (Threshold 600 A) | 120 | 27 | 60 | 33 |
51N.S1 Two-phase to ground fault | 170 | 27 | 60 | 83 |
67N.S2 One-phase to ground fault with not compensated neutral | 170 | 57 | 60 | 53 |
67N.S1 One-phase to ground fault with not compensated neutral | 450 | 57 | 60 | 333 |
51.S2 Poly-phase short circuit (Threshold 250 A) | 500 | 57 | 60 | 383 |
Table 10.
Values of in ms depending on BW and SF, with CR = 1, CRC disabled, and implicit header. The red color indicates values of the table that are not feasible. The green color indicates values of the table that are feasible.
Table 10.
Values of in ms depending on BW and SF, with CR = 1, CRC disabled, and implicit header. The red color indicates values of the table that are not feasible. The green color indicates values of the table that are feasible.
| SF |
---|
BW | 7 | 8 | 9 | 10 | 11 | 12 |
---|
125 | 30.98 | 51.71 | 103.42 | 209.85 | 413.70 | 827.39 |
250 | 15.49 | 30.98 | 51.71 | 103.42 | 209.85 | 413.70 |
500 | 7.74 | 15.49 | 30.98 | 51.71 | 103.42 | 209.85 |
Table 11.
Estimated time intervals during the fault 50.S3 between SR and PR1.
Table 11.
Estimated time intervals during the fault 50.S3 between SR and PR1.
Interval | Measurement Method | Max Value [s] | Measured Value [s] |
---|
| - | 0.03300 | 0.03297 |
| - | - | 0.05146 |
| - | - | 0.06969 |
| - | - | 0.08824 |
| - | - | 0.10796 |
Table 12.
Estimated time intervals during the fault 50.S3 between PR2 and PR3.
Table 12.
Estimated time intervals during the fault 50.S3 between PR2 and PR3.
Interval | Measurement Method | Max Value [s] | Measured Value [s] |
---|
| - | 0.03300 | 0.01827 |
| - | 0.03300 | 0.01827 |
| - | 0.03300 | 0.03296 |
| - | - | 0.05149 |
| - | - | 0.07085 |
Table 13.
Time intervals for fault clearing and interconnection reclosure for the fault 50.S3.
Table 13.
Time intervals for fault clearing and interconnection reclosure for the fault 50.S3.
Case Study | Interval | Measured Value [s] |
---|
Fault clearing time for fault 50.S3 between SR and PR1 | | 0.03297 |
Fault clearing time for fault 50.S3 between PR2 and PR3 | | 0.03296 |
Reclosure time for fault 50.S3 between SR and PR1 | | 0.10796 |
Reclosure time for fault 50.S3 between PR2 and PR3 | | 0.07085 |
Table 14.
Values of in ms depending on BW and SF, with CR = 1, CRC disabled, and implicit header. The red color indicates values of the table that are not feasible. The green color indicates values of the table that are feasible.
Table 14.
Values of in ms depending on BW and SF, with CR = 1, CRC disabled, and implicit header. The red color indicates values of the table that are not feasible. The green color indicates values of the table that are feasible.
| SF |
---|
BW | 7 | 8 | 9 | 10 | 11 | 12 |
---|
125 | 30.98 | 51.71 | 103.42 | 209.85 | 413.70 | 827.39 |
250 | 15.49 | 30.98 | 51.71 | 103.42 | 209.85 | 413.70 |
500 | 7.74 | 15.49 | 30.98 | 51.71 | 103.42 | 209.85 |
Table 15.
Estimated time intervals during the fault 67N.S1 between SR and PR1.
Table 15.
Estimated time intervals during the fault 67N.S1 between SR and PR1.
Interval | Measurement Method | Max Value [s] | Measured Value [s] |
---|
| - | 0.33000 | 0.32839 |
| - | - | 0.54391 |
| - | - | 0.76427 |
| - | - | 0.98106 |
| - | - | 1.19899 |
Table 16.
Estimated time intervals during the fault 67N.S1 between PR2 and PR3.
Table 16.
Estimated time intervals during the fault 67N.S1 between PR2 and PR3.
Interval | Measurement Method | Max Value [s] | Measured Value [s] |
---|
| - | 0.33000 | 0.21579 |
| - | 0.33000 | 0.21580 |
| - | 0.33000 | 0.32957 |
| - | - | 0.54589 |
| - | - | 0.76248 |
Table 17.
Time intervals for fault clearing and interconnection reclosure for the fault 67N.S1.
Table 17.
Time intervals for fault clearing and interconnection reclosure for the fault 67N.S1.
Case Study | Interval | Measured Value [s] |
---|
Fault clearing time for fault 67N.S1 between SR and PR1 | | 0.32839 |
Fault clearing time for fault 67N.S1 between PR2 and PR3 | | 0.32957 |
Reclosure time for fault 67N.S1 between SR and PR1 | | 1.19899 |
Reclosure time for fault 67N.S1 between PR2 and PR3 | | 0.76248 |
Table 18.
Estimated time intervals during the fault 67N.S1 between SR and PR1, with a LoRa of 103.42 ms.
Table 18.
Estimated time intervals during the fault 67N.S1 between SR and PR1, with a LoRa of 103.42 ms.
Interval | Measurement Method | Max Value [s] | Measured Value [s] |
---|
| - | 0.33000 | 0.32837 |
| - | - | 0.43706 |
| - | - | 0.54803 |
| - | - | 0.65740 |
| - | - | 0.76795 |
Table 19.
Estimated time intervals during the fault 50.S3 between PR3 and TR.
Table 19.
Estimated time intervals during the fault 50.S3 between PR3 and TR.
Interval | Measurement Method | Max Value [s] | Measured Value [s] |
---|
| - | 0.033000 | 0.01827 |
| - | 0.03300 | 0.01828 |
| - | 0.03300 | 0.01828 |
| - | 0.03300 | 0.03297 |