Arc Flash Detection and Mitigation

Transcription

1 Summary Arc flashes in switchgear and drives imply: 1. the risk of injury to site personnel, as well as 2. damage to the affected equipment. Switchgear offers passive arc mitigation solutions (safety by design, defined by standards) and on top of that active arc mitigation technologies. But also MV Drives have solutions at the forefront of arc flash safety (ABB MV Drives have defined 4 classes for arc fault protection) This presentation outlines the different steps and how they make a difference. February 18, 2017 Slide 1

2 GAS/ELECTRIC PARTNERSHIP CONFERENCE, HOUSTON, FEB. 9 TH 2017 Arc Flash Detection and Mitigation Tanner Knecht, Project Proposals Manager, ABB Drives and Controls, MV and High Power Drives Thomas Schmidtchen, Global Oil and Gas Segment Manager, ABB MV Electrification Products

3 Passive arc mitigation safety by design Arc resistant switchgear Pressure relief plenums integrated in the switchgear design February 18, 2017 Slide 3

4 Passive arc mitigation safety by design Non-arc resistant switchgear Arc resistant switchgear Maximized personnel safety February 18, 2017 Slide 4

5 Active arc mitigation Mechanical microswitches (on pressure relief flaps) Optical sensors and CTs (flash + current = trip) ABB s UFES (Ultra-fast Earthing Switch) A B C Arc cleared in ms Arc cleared in ms Arc cleared in <4ms Multiple solutions for highest personnel and equipment safety February 18, 2017 Slide 5

6 Active arc mitigation via Ultra-fast earthing switch (UFES) W/o grounding switch (arc duration 100ms) With grounding switch (arc duration <4ms) February 18, 2017 Slide 6

7 Medium Voltage Drives Standards with arc resistant design requirements Standards without arc resistant design requirements Switchgear Power Electronic Converters Drives IEC IEC High-voltage switchgear and controlgear IEC Safety requirements for power electronic converter systems and equipment IEC Safety requirements, Electrical, thermal and energy NEMA IEEE C IEEE Guide to test metal-enclosed switchgear non IEC Safety requirements, Electrical, thermal and energy UL UL347 Medium-Voltage AC Contactors, Controllers, and Control Centers UL347 (a) Medium Voltage Power Conversion Controllers none Presently there is no relevant standard released for arc resistant design of MV drives. ABB and other companies have applied switch gear standards. IEC and IEEE are very similar A new IEC standard relevant for MV drives will be released soon (IEC ) This standard will be relevant in IEC world and likely also in NEMA world The standard allows to reuse the certifications according switchgear standards This are most relevant standards for MV (and LV) drives safety requirements. Future revision will reference to IEC62477 (-1 for LV) and (-2 for MV) for arc resistant design February 18, 2017 Slide 7

8 Arc resistant design IAC Certified according IEC Arc Flash Detection and Mitigation Medium Voltage Drives Class I - protection based on arc prevention Design of insulation systems in accordance with relevant IEC and NEMA standards Class I is not an certified arc resistant design, it is mainly focusing of arc fault prevention. Class II - protection based on cabinet structure The cabinet is designed to withstand the pressure of an arc flash Arc fault is contained in the cabinet or guided through pressure relief vents. The drive will be face severe damage after an event. Class III - protection based on external arc fault limitation and elimination HV Fuses are applied externally to the drive in order to limit the arc fault current to less than half cycle of the fundamental AC frequency (< 10ms in case of 50Hz supply) This method is only used to reach arc resistant designs for MV drives connected without external drive transformer to the mains (integrated transformer solutions and DTL solutions). Class IV - fast arc elimination This is a ABB patented method, which combines fast optical arc fault detection and ABB MV drives protection firing system. The arc fault is detected and converted into a non severe bolted short circuit within 4 8ms. Provides highest level of personal safety and the equipment remains undamaged and can be immediately restarted after inspection and elimination of the arc ignition cause. February 18, 2017 Slide 8

9 Medium Voltage Drives Product ABB class Rating ACS1000a II IAC AFLR 5kA / 0.5s ACS1000w II IAC AFLR 6kA / 0.5s optional: 15kA / 0.5s ACS2000 DFE IEC II IAC AFLR 15kA / 0.45s IV IAC AFLR 18kA / 0.5s ACS2000 AFE IEC II IAC AFLR 3.5kA / 0.5s ACS5000a non ACS5000w IV IAC AFLR 56kA / 0.5s ACS6000 II IAC AFLR 20kA / 0.5s IV IAC AFLR 50kA / 0.5s LCI (w) II IAC AFLR 23kA / 0.5s Main power line Input section Input transformer Rectifier DC-link Inverter Output filter Motor 50 M February 18, 2017 Slide 9

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