MAINTENANCE STANDARDS SPECIFICATION TITLE Power System Study Procedure VALE # Ontario Operations MPROC-50003 VALE # October 14, 2016 PAGE 1/14 Rev 3 Training Code (not applicable) Document Owner: Name: Phil Langlois Department: Lead Engineer Table of Contents 1. PURPOSE... 2 2. APPLICATION... 2 3. EXCEPTIONS... 2 4. REFERENCE DOCUMENTATION... 3 5. COMMITMENTS... 3 6. DEFINITIONS... 4 7. TOOLS... 5 8. ENGINEERING REQUIREMENTS... 5 9. DELIVERABLES... 12 10. APPENDICES... 13 Page 1 of 14
1. PURPOSE This procedure describes the methodology for dealing with power system studies; it is understood that the study should include a short circuit study, a device evaluation, a protective device coordination study (phase & ground), and an arc flash study. Standardizing the studies within the Vale Ontario division will ensure that higher quality studies are produced consistently, thereby making them easier to use and update as required. Furthermore, this standardization will minimize unnecessary duplication within the document. If a large site is fed by more than one main incoming substation/transformer, the site may elect to have more than one study. This will allow for a quicker completion turn-around time, facilitate ongoing revisions/addendums, and will assist in the recommended 5-year updates. 2. APPLICATION A new study will not be created if a completed study is available. The existing study will therefore be updated; or an addendum to the study will be issued. The following examples are guides to clarify what types of changes will necessitate a study update: adding/removing MPCs or MCCs or new 600V distribution racks, changes to settings or fuse sizes which cause posted labels to be inaccurate to the point that posted PPE will no longer adequately protect workers, adding a large load to a main rack that is fed with large protective devices which might interfere with the existing coordination. The following examples would not necessitate study updates but rather the creation of an addendum and would be incorporated during the 5-year updates: adding/removing loads on any of the 600V distribution racks. 3. EXCEPTIONS This procedure, applies at all Vale Ontario operation locations No exceptions to these procedures will be permitted without specific permission by the Vale Specialty Engineering Department. Page 2 of 14
4. REFERENCE DOCUMENTATION The following references were used in the development of this document. Engineering Standard Design Guide SPEC-50001- Guidelines for Power System Studies 3 Phase A.C. Systems 5. COMMITMENTS The latest issues, amendments, and supplements of the following standards shall apply to this procedure, unless stated otherwise: CSA M421-11 - Use of Electricity in Mines CSA Z462-15 - Workplace electrical safety IEEE 1584-2002 - Guide for Performing Arc-Flash Hazard Calculations IEEE Standard 141-1993 - Recommended Practice for Power Distribution for Industrial Plants (Red Book) IEEE Standard 142-1991 - Recommended Practice for Grounding of Industrial and Commercial Power Systems (Green Book) IEEE Standard 242-2001 - Recommended Practice for Protection and Coordination of Industrial and Commercial Power Systems (Buff Book) IEEE Standard 551-2006 - Recommended Practice for Calculating Short Circuit Currents in Industrial and Commercial Power Systems (Violet Book) IEEE C37.010 - Application Guide for AC High Voltage Circuit Breakers Rated on a Symmetrical Current Basis IEEE C37.5 - Guide for Calculation of Fault Currents for Application of AC High Voltage Circuit Breakers Rated on a Total Current Basis IEEE C37.13 - Standard for Low Voltage AC Power Circuit Breaker NFPA 70E-2015 - Standard for Safety in the Workplace OESC-2015 - Ontario Safety Code Page 3 of 14
6. DEFINITIONS For the purpose of this procedure, the terms and definitions as identified in IEEE Standard 1584 and CSA Standard Z462 shall apply. For any terms not defined in this standard, IEEE Standard 100 - The Authoritative Dictionary of IEEE Standard Terms; shall be referred. Further definitions include the following: ARM Arc Reduction Maintenance TCC Time-Current Curve Page 4 of 14
7. TOOLS Software used for modeling and analyzing must include the latest revision of EasyPower. No software substitution is permitted. Longhand calculations performed by a professional engineer licensed by the province are acceptable for small systems; or for cases for which the software does not have provisions or yields anomalous results. 8. ENGINEERING REQUIREMENTS To assist in the preparation and publishing of a study, a completed study example will be provided to ensure symmetry to all other studies for the division. Plant and mine personnel must be able to navigate each study to obtain required information without having to re-learn the process at each site or for different studies. The layout and design of the study report will include: Section Content Description Title Page The title page will show: customer and consultant names; consultant s project identifier; brief substation description and identifier; month and year of issue; and tabled summary of the last five revisions. Table of Contents The table of contents will identify subsection titles and page numbers. Table of Appendices The order must be consistent with the suggested format to allow plant personnel to quickly locate tables, TCCs, diagrams and charts. A disclaimer page may be included by the consultant. Section 1.0 Scope of Work and Objectives Subsection #0 is reserved for the scope of work and objectives. Subsection #1 is reserved for the computer software details. Subsection #2 is reserved for the revision summary. The original release will be called Revision 0 ; with all significant subsequent revisions incrementing by one. Page 5 of 14
Section Content Description If a minor revision or addendum is issued, the number will remain the same; however, a letter will be added to the extension (i.e. Rev 1A, 1B, etc.). Detailed descriptions will be given regarding the nature of subsequent revisions; such as additions, deletions, and mitigation. Section 2.0 Executive Summary An executive summary that only summarize where the results of each study can be found within the report in order to avoid duplication. Section 3.0 Methodology Subsection#0 indicates how the information was collected and by whom; and gives the utility min/max fault contributions, and the dated source of this information. Fault contribution levels from previous studies will also be kept. Subsection #1 contains the table of all possible distribution scenarios. Scenario 1 is always the normal case. Arc flash labels will be printed to match the worst case of all scenarios except those assuming main substation tie-breaker closures, transformer paralleling or emergency/backup operation. Only the main substation breakers will have labels using the paralleling scenario. The device evaluation will use the normal case and the paralleling case. Buses which can be fed from a generator or have ARM switches are given a dual value label since arc flash values differ greatly from the other cases. Vale understands and assumes all liability for risks that arise when two incident values are displayed on a single piece of equipment. Section 4.0 Short Circuit Study and Device Evaluation Definitions, information, and explanations regarding the short circuit study and device evaluations are given. Appendix C is to be referenced. Page 6 of 14
Section Content Description Subsection#3 tables present all marginal and overdutied distribution and protection equipment along with which scenario they belong to. Recommendations will be made to resolve strictly the over-duty issues. Section 5.0 Section 6.0 Protective Device Coordination Study Arc Flash and Shock Risk Assessment This section is not only for problem areas but for the whole distribution and for both phase and ground faults. After a quick description regarding the intended purpose and the guidelines used, Appendix B is to be referenced. Subsection#2 must not only look at selectivity but also at electrical code compliance and must ensure that incident energy is not increased with the proposed settings. These results and general recommendations will be given for each TCC thereby keeping details in Appendices E and I. A tabular format presentation of recommendations can be used. Definitions, information, and explanations regarding the arc flash study are given. Incident energy calculations shall be made based on calculated arcing currents. Appendix D is to be referenced. Recommendations are expected for all buses with incident energies greater than 8 cal/cm 2. Do not indicate the exact calculated incident energy but rather use categories such as >8, >8 but<12, >12 but <25, >25 but <40, or >40. Where the most recent arc flash standard, definitions, and generic report body has already been presented in an earlier report version of the same area, subsequent addendum do not need to present the same body. This generic body needs only to be updated when: there is an update to the Standard or when issuing a full update. Page 7 of 14
Section Content Description Section 7.0 Signatures and References When making any reference to a standard, the date will be omitted and kept only in subsection 7.2 to avoid further updating needs. Appendix A Impedance Diagrams This appendix will include: a list of all impedance diagrams; and all legible impedance diagrams are to be presented in ledger (11 x 17) format. While modeling >600 V equipment, a bus must be selected for each piece of equipment, so that switch room and field labels can be applied on all equipment. While modeling the 600 V equipment, all main switch room equipment will be labeled; but only the field equipment rated >1.2cal/cm 2 will be labeled to minimize the number of labels. To accomplish this, a fictitious fused disconnect labeled as FD- will be added with the largest fuse on that rack - its cable size and a fictitious length of cable to mimic the longest possible cable length, or worst case to show that all downstream equipment is rated <1.2cal/cm 2 and does not otherwise need labeling. When modeling the motor loads, group all <50 HP motors together while grouping the >50 HP together. Show the largest loads/motors by themselves if rated over 1.2cal/cm 2. Motors which are >50HP and utilize a VFD, are to be modeled independently and a label is to be supplied for the VFD. Modeling of loads <600 V will be required if the 3-phase supply transformer is larger than 125kVA (even though some industry best practice is suggesting 75kVA, IEEE 1584 and CSA- Z462 mention that transformers smaller than 125kVA need not be included). All distribution data assumptions will be shown in a box format so that they cannot be missed. Single phase loads do not need to be modelled. For assumptions that are made which cannot be confirmed later (such as fallen nameplates resulting in assumed impedance ), these will be marked directly on the impedance diagrams. Page 8 of 14
Section Content Description Appendix B TCCs List all TCCs numbers followed by the TCCs. Colour TCC curves to be issued will have a single line beside them on the left side. To maintain a historical record of all installations, each TCC will have up to three possible versions: original, present/existing/current, and recommended settings. Vale may decide to eliminate original TCCs during some updates. For all 600 V ground fault feeder breaker TCCs on solidly grounded systems, a 60 A Mersen AJT fuse curve will be shown to remind the plant of this minimum coordination requirement. Numbering of the ground curves will start at 50 or 100 to avoid having to re-number existing phase TCCs when new ones are added or deleted (depends on the size of the study). These will all be printed on 8.5x11 paper in a matter such as to minimize the number of sheets required (tweaking with scale, font size ). Appendix C Short Circuit and Equipment Duty Tables List of HV and LV momentary tables and equipment duty tables followed by the tables themselves for the normal scenario and the paralleling scenario. The equipment duty results table will be color coded in black for acceptable, orange for marginal and, red for overdutied Marginal is defined as being between 80% and 100% dutied. These will all be printed on 8.5x11 paper in a matter such as to minimize the number of sheets required (tweaking with scale, font size ). Page 9 of 14
Section Content Description Appendix D Arc Flash Summary Tables A list of all tables will be made available for all scenarios. A separate worst-case scenario table will also be issued. The worst-case table will be issued containing: arc flash protection boundary in feet-inches; working distance in inches; incident energy level in cal/cm 2 ; required Vale PPE level the number of labels issued, and scenario which resulted in the worst-case for each bus (to name a few). Not all labels will necessarily be printed from the same scenario. Where it makes sense to do so, provide a second working distance which would drop incident energy levels when using a racking device extension, an ARM switch or working with a hotstick. Some labels may contain two sets of numbers for arc flash boundaries and incident energy levels. The worst-case summary table is to be provided in Ledger (11x17) format. Appendix E Assumptions and Recommendations All document assumptions must be listed in this appendix. The action item tables are to be divided into the following three groups: E-1 for equipment duty; E-2 for protective device coordination; and E-3 for arc flash study. The E-3 table will have a column which shows recommended mitigation or permanent/temporary measure(s) which have to been taken (brief). It will be the site s responsibility to obtain missing information, verify assumptions, correct the issues or implement solutions before the next revision of the document. Page 10 of 14
Section Content Description During the initial or early study revisions which contain many recommendations, the tables may refer to Appendix I for setting changes, to avoid duplicating a large number of recommendations. Appendix F Vale Single Line Drawings A list of all single line drawings and their revision numbers grouped into practical subsections to make the 5 year updates easier. The plants may store their drawings in this section but are not required to be included as part of the study. Appendix G Photographs Photos can be provided but must be supported by a list of photos for ease of identification. Photos should be trimmed to focus on electrical equipment. All worker faces may be blurred to maintain privacy. All pictures should be of a reduced quality format in order to maintain the document at a reasonable size. Appendix H Appendix I Reference Documents Protective Device Settings Summary List of all documents followed by the relevant documents. This section should be kept as small as possible. This section will consist of a PDF copy of the spreadsheet showing all relevant fuses and relay settings, and also all low voltage breaker settings. Original settings and changeover dates will be kept. Outstanding items will be highlighted in yellow. The Protective Device Settings Summary table is to be provided in Ledger (11x17) format. Page 11 of 14
9. DELIVERABLES The following deliverables will be supplied by Vale and external consultants as required; to assist in the preparation of the study. Vale-Supplied Deliverables All single line drawings from the substation to the most downstream switch room connected loads (Specialty Engineering will provide with assistance from the plant electrical contact); All fuse sizes and types (the plant or mine electrical contact will confirm the accuracy of the drawings and obtain the missing information using planned shutdowns); All asfound protective device settings (Specialty Engineering to request this information from the Vale Power Department s P&C Group); Minimum and maximum available fault contributions (Specialty Engineering to request this information from the Vale Power Department s Engineering Group); All missing information not requiring the consultant s expertise (such as cable lengths) shall be obtained by the plant or mine electrical contact after receiving such requests; in order to maximize efficiencies and lower costs; The plant or mine may choose to provide a photo record of the site installation (Optional); If a study already exists, it will be made available for updating; and An MS Excel template of protective devices and settings will be provided. Consultant-Supplied Deliverables Paper copies (color): one (1) binder for the plant or mine and one (1) binder for Specialty Engineering. For larger studies, the binder will be an 11x17 binder.; Electronic report - The electronic report containing the model (.dez format), the report (.pdf format) and the device settings spreadsheet (.xlsx format) shall be sent in three separate documents to Specialty Engineering. Vale will own the model, the report, and the Excel files; The modeling software must be EasyPower and the bus names must be plant specific and not generic (plant electrical contact must agree with convention); A spreadsheet containing all 600V-69,000V fuses, adjustable relay, and breaker settings shall be provided for the plant or mine s future use; and Issue the labels in an easy to post order/format. Page 12 of 14
10. APPENDICES Appendix A Revisions Notes and Approvals Page 13 of 14
Appendix A: Revision Notes and Approvals Note: The revision notes are a summary of the changes and may not necessarily be a complete list. Refer to the document owner for reference to previous versions. Revision Notes 3 Aligned procedure with existing practices of the last 4 years. Updated reference documents to recent versions: CSA Z462-15, NFPA 70E- 2015 and OESC-2015 Standard applies to Vale Ontario operations reference to North Atlantic removed. Table of Contents added to document. 2 SPI-ENG-0003 Power Study Procedure Rev: 1-7/9/2012 reformatted to Maintenance Standard document: MPROC-50003 Power System Study Procedure. 1 SPI-ENG-0003 Initial document 7/9/2012 Page 14 of 14