Do
HW06.pdf
Download HW06.pdf
protection and coordination study. Model
DISTRIBUTION Feeder HW06.olr
Download DISTRIBUTION Feeder HW06.olr
Coordination Table
HW06 Coord Summary.xlsx
Download HW06 Coord Summary.xlsx
and PS50 Criteria
PS-50 Distribution Feeder Protection excerpt.pdf
Aspen username: sa5t6
Password: Legendkiller!123
Deadline is Saturday (3/11/23)
HW06 EE6560 Power System Protection 1 Do 12.47kV distribution protection and coordination. The HW06 ASPEN model, coordination summary table, and an excerpt from Ameren PS-50 are on Canvas as your starting point. The model already has the network model, a Recloser with settings, Grocer customer 480V breaker settings, and Ameren 14G standard 12.47kV feeder device 51 and 51N settings. You are allowed to change the 12kV 51 and 51N settings and the Recloser type & size though you must explain your reasoning. 1. Please specify fuses at Point M, Grocer high side (HS), and Point P. Refer to completed coordination table and TCC to explain. (30 points) 2. Choose the 34.5/12.47kV substation main breaker device 51 and 51N types, CT ratio, and specify settings. Refer to completed coordination table and TCC to explain. (50 points) 3. Simulate the required faults and complete the coordination table; (you may need separate phase and ground coordination tables.) (40 points) 4. Provide PDF of Time-Current Curves (TCC) for (30 points) a. Grocer transformer damage curve, fuse, and LS breaker settings b. Feeder phase protection c. Feeder ground protection 5. Criteria: a. In general our minimum Detection Margin = 1.5 (with 2 preferred), and minimum Load Margin is 1.15, and substation relay minimum Coordinating Time Interval (CTI) = 0.3 seconds. b. PS-50 provides feeder protection and coordination criteria. c. Strive to minimize total clearing times. Paul Nauert 3/6/2023 HW06 Coord summary #Protective DeviceLoad Current towardProtection ZoneLoad (A)MTO (A)Load marginFault typeMin EOL Bolted FaultDetection MarginSmallest upstream deviceUpstream CTI (sec)Largest downstream deviceDown-stream CTI (sec)Notes Main 51MFeedersSubstation bus1500N/AFdr Dev 51F Fdr Dev 51FPoint MSubstation breaker to Recloser4836001.24ph-ph14782.46Main breakerrecloserph-ph EOL shown as example Point M __ fuseVeldaPoint M-Velda122Fdr Dev 51F65T fuse Grocer HS fuseGrocer new load12.47kV ∆ / 480V Y 1500kVA transformer62Fdr Dev 51F480V panel main Recloser with 2 Fast & 2 Slow curvesPoint PRecloser to Point P135Fdr Dev 51FPoint P fuse Point P tap fuseBus SPoint P to Bus S55recloser Load amps include the new grocery store being added at Point M All at nominal 12.47kV, except Grocer Low Side (LS) is 480V. CTI means Coordinating Time Interval in seconds Min EOL means the minimum bolted fault current at the End Of Line, i.e. the end of the protected zone. Date DISTRIBUTION FEEDER PROTECTION Standard Revision PS-50 4 12/12 Electrical Distribution Design Standard Sheet 12 of 64 4.0 PROTECTIVE DEVICE APPLICATION The criteria / guidelines for protective device application on distribution circuits are listed as follows: 1) The protective device voltage rating must meet or exceed the system operating voltage. 2) The protective device interrupting capability must exceed the maximum bolted fault current (3-phase or phase-ground) at the point of application. 3) The protective device must be able to detect minimum end-of-line bolted faults within its zone of protection with a margin of 1.5 or greater. A margin of 2.0 or greater is preferred. 4) The protective device must coordinate with upstream and downstream protective devices. Lock out coordination must be achieved when two protective devices are connected in series however; trip coordination may or may not be achieved. 5) The protective device must be able to carry maximum continuous loads without damage or false tripping. Protective device application is for fault isolation, not overload protection. 6) The protective device must be able to carry load during contingency conditions without damage or false tripping. Contingency conditions include cold-load pickup and circuit switching. Examples of protective device application on various types of distribution circuits are provided in Section 8.0. 4.1 Fuse Application Fuse voltage rating should meet or exceed the system operating voltage. Fuse symmetrical interrupting rating should exceed the maximum bolted fault level at the point of application. In areas near 4kV substations, the interrupting rating of T-link fuses may be exceeded. In these situations, SMU-20, SM-4, or SM-5 fuses need to be installed to meet required interrupting capability. In areas near 12kV substations, the interrupting rating of T-link fuses may be exceeded. In these situations, SMU-20 fuses need to be installed to meet required interrupting capability. Fuse total clear curve should detect minimum end-of-line bolted faults with a margin of 1.5 or greater. A fault detection margin of 2.0 or greater is preferred. Maximum normal and contingency loads should not exceed the fuse manufacturer’s published continuous and 8 hour ratings respectively. Date DISTRIBUTION FEEDER PROTECTION Standard Revision PS-50 4 12/12 Electrical Distribution Design Standard Sheet 13 of 64 Coordination requirements are as follows: Fuse-Fuse Coordination The upstream fuse must not be damaged by a fault beyond the downstream fuse. The total clearing time of the downstream fuse should be less than 75% of the upstream fuse minimum melt time. Fuse-fuse coordination is shown in Tables 4-1 through 4-4. In general, for fuses of the same curve shape, fuses in series should be offset by two sizes in order to coordinate. Hydraulic Recloser-Fuse Coordination The upstream recloser must not lock out for a fault beyond the downstream fuse. To ultimately achieve lock out coordination using hydraulic reclosers, a time margin of at least 0.1 second between the total clearing time of the fuse and the recloser delayed time is required. Also, the recloser can be used to clear temporary faults downstream of the fuse, without damaging the fuse, by operation on its fast curve. To achieve fuse savings, a time margin of 0.1 second between the recloser fast curve and the fuse minimum melt curve is required to prevent damaging the fuse. As such, recloser-fuse combinations that meet these two constraints over the applicable fault current range are preferred. However, recloser-fuse combinations that provide lock out coordination are required. Recloser-fuse coordination is shown in Table 4-5. Circuit Breaker/Electronically Controlled Recloser-Fuse Coordination The upstream circuit breaker/electronically controlled recloser must not lock out for a fault downstream of the fuse. To ultimately achieve lock out coordination, a time margin of at least 0.1 second between the total clearing time of the fuse and the overcurrent relay time is required. The circuit breaker/electronically controlled recloser may be used to clear temporary faults downstream of the fuse, without damaging the fuse, by operation of an instantaneous relay. To achieve fuse savings, a time margin of 0.1 second between the instantaneous relay operating time plus the breaker clearing time and the fuse minimum melt curve is required to prevent damaging the fuse. As such, circuit breaker/electronically controlled recloser-fuse combinations that meet these two constraints over the applicable fault current range are preferred. However, circuit breaker/electronically controlled recloser-fuse combinations that provide lock out coordination are required. Circuit breaker-fuse coordination is discussed further in Section 6.0. The largest fuses that coordinate with the standard breaker settings are listed in Section 6.2. Standard electronically controlled recloser-fuse coordination is shown in Table 4-5.Line Recloser Application Date DISTRIBUTION FEEDER PROTECTION Standard Revision PS-50 4 12/12 Electrical Distribution Design Standard Sheet 14 of 64 4.2 Line Recloser Application Recloser voltage rating should meet or exceed the system operating voltage. Recloser symmetrical interrupting rating should exceed the maximum bolted fault level at the point of application. Recloser MTO must be less than the minimum end-of-line bolted faults with a margin of 1.5 or greater. A margin of 2.0 or greater is preferred. Hydraulic recloser MTO is typically twice its rating. Hydraulic reclosers with an X designation (400X or 560X) have an MTO of 1.4 times its rating. Relay / Microprocessor controlled recloser MTO is based on the trip settings of the phase and ground elements. Maximum normal and contingency loads should not exceed the recloser manufacturer’s published continuous and 8 hour ratings respectively. Per Cooper Power Systems, hydraulic recloser emergency ratings are 125% of the trip coil rating. Typically, hydraulic reclosers will have two fast and two delayed operations before locking out. S&C Intellirupters are electronically controlled reclosers used for backbone protection. See section 5.2 for more details. S&C Tripsavers are small reclosers that fit universal cutout fuse mountings. Tripsavers are used in place of tap fuses for fuse saving. See Section 5.2 for more details. Coordination requirements are as follows: Recloser-Fuse Coordination See section 4.1. Recloser-Sectionalizer Coordination See section 4.3. Recloser-Recloser Coordination The upstream recloser must not lock out for a fault beyond the downstream recloser. To achieve lock out coordination, a time margin of at least 0.2 second between the delayed curves of both reclosers is required. Trip coordination may be achieved between electronically controlled reclosers and hydraulic reclosers however; trip coordination will rarely be achieved between hydraulic reclosers. The upstream reclosers may trip on their fast curves when the downstream reclosers trip on their fast curves. If not, then the upstream reclosers may trip on their fast curves when the downstream reclosers trip on their delayed curves. Recloser-recloser coordination is shown in Table 4-6. Date DISTRIBUTION FEEDER PROTECTION Standard Revision PS-50 4 12/12 Electrical Distribution Design Standard Sheet 15 of 64 Circuit Breaker-Recloser Coordination The upstream circuit breaker must not lock out for a fault beyond the downstream recloser. To achieve lock out coordination, a time margin of at least 0.3 second is required between recloser delayed operation and the overcurrent relay curve for microprocessor based relays with instantaneous reset. For circuit breakers with electromechanical relays which have time delay reset, a time margin of at least 0.1 second is required between the total time of all delayed operations of the hydraulic recloser and the overcurrent relay curve of the circuit breaker. Also, a time margin of at least 0.3 second is required between the delayed operations the electronically controlled recloser and the overcurrent relay curve of the circuit breaker. To achieve trip coordination, the instantaneous relay setting of the circuit breaker must be at least 120% of the maximum bolted fault current at the recloser. However, in order to provide fuse savings on the remainder of the circuit, the instantaneous relay setting is not usually altered to achieve trip coordination. Circuit breaker-recloser coordination is discussed in Section 6.0. The largest reclosers that coordinate with the standard breaker settings are listed in Section 6.2. Date DISTRIBUTION FEEDER PROTECTION Standard Revision PS-50 4 12/12 Electrical Distribution Design Standard Sheet 18 of 64 4.4 Distribution Transformer Protection Each phase of a transformer bank is protected by a fuse. Fuse voltage rating should meet or exceed the system operating voltage. Fuse symmetrical interrupting rating should exceed the maximum bolted fault level at the point of application. Fuse total clear curve should detect transformer low-side bolted faults with a margin 1.5 or greater and protect the transformer damage curve. For single-phase and three-phase wye-wye transformers, low-side faults are reflected to the high-side via the turns ratio. For three-phase delta-wye transformers, low-side phase-to-ground faults are reflected to the high-side via the turns ratio x 0.577. Low-side multi-phase faults are reflected to the high-side as the three-phase fault level via the turns ratio. Fuse total clear curve should plot below the transformer damage curve. Damage curves are developed per ANSI C57.12 standard. For a category I transformer (5-500kVA single or three-phase) the damage curve is 25 times full load current at 2.0 seconds and 12.5 times full load current at 8.0 seconds (I2T = 1250). For a category II transformer (501-1667kVA single-phase and 501-5000kVA three-phase) the damage curve is 2.0 seconds at maximum low-side fault, and 4.0 seconds at 0.7 x maximum low- side fault. For delta-wye transformers the damage curve must be shifted by 0.577 for phase- ground faults. Maximum low-side faults are calculated assuming infinite source bus. Note the category II damage curve includes a frequent fault branch based on transformer impedance which must be protected. Fuse minimum melt curve should exceed transformer magnetizing inrush current and allow a minimum 0.3 seconds coordination time with low-side protection. Conservative estimates of the worst case magnetizing inrush currents are 12 times the nameplate current rating for 0.1 second and 25 times the nameplate current rating for 0.01 second. Maximum normal and contingency loads should not exceed the fuse manufacturer’s published continuous and 8 hour ratings respectively. Distribution transformer loading and impedance data is shown in Table 4-7. This data was used as the basis to determine the appropriate fuse size. Date DISTRIBUTION FEEDER PROTECTION Standard Revision PS-50 4 12/12