Developed and Presented By: Adrian G Zvarych, PE Principal Engineer TRC Engineering Member, IEEE

1. PRESENTATION TO IEEE PES, ORLANDO CHAPTER:“GROUNDING & BONDING CONSIDERATIONS FOR SUBSTATION COMMUNICATIONS AND “SMART GRID”” Developed and Presented By: Adrian G Zvarych, PE Principal Engineer TRC Engineering Member, IEEE 24 September 2009 azvarych@trcsolutions.com Additional Contributions & Peer Review By: Michael Cunningham, Senior Engineer - TRC

2. Class Objectives • Understand Substation Grounding/Bonding Design Goals to Satisfy Communications Requirements • Review of Typical Substation Control House Grounding/Bonding Practices • Review Typical Telecom Room Grounding/Bonding Practices • Necessary Grounding & Bonding Elements for a Smart Grid Friendly and Communications – Ready Substation Control House • Look-Ahead for other opportunities • Review 40 Years of Service 1969 2009

3. Change Has Been Happening 40 Years of Service 1969 2009

4. Part 1: Substation Communications Evolution • Communications migration path: • Analog to digital • Discrete to multiplexed • Local Information decision needs to remote and diverse needs • Lower Reliability to High Reliability (design and need) • Minimal regulation (self- on inter-industry regulation to increased scrutiny and regulation by others) 40 Years of Service 1969 2009

5. Pilot Wire Interface & Isolation Transformers

6. Circa 1900’s Distribution Breakers 1912 – Manufactured GE Oil Break Switch… STILL IN SERVICE!!!!

7. Legacy Substation Communications Systems PEOPLE/OPERATIONS • Station Operators with all local indication • Communications to Control Center via Power Line Carrier or Telephone Company Copper Circuits (SCADA) • Radio Dispatch for Crews RELAY PROTECTION • Power Line Carrier (first digital form of substation communications “ON-OFF”) • Copper Based Pilot Wire • All analog meters and electromechanical relays • Needs driven by electric utility operations & reliability 40 Years of Service 1969 2009

8. Advancements in Legacy Substation Relaying and Communications • Driven by build out of high voltage and EHV transmission grid • Need for high speed and reliable/secure relaying • Need for remote and central monitoring and control of station equipment • First discrete component “solid state” relaying deployed in substations in the 1970s • Single Side-Band Power Line Carrier – more channels, more functionality • Analog Point-To-Point Microwave • Optical Networks 40 Years of Service 1969 2009

9. Development of “Non-Copper” Substation Communications Systems • Analog Microwave (circa 1960’s) • Digital Microwave (circa 1980’s) • Spread Spectrum – 900MHz (circa 1980’s) • Fiber (circa 1990’s) 40 Years of Service 1969 2009

10. Advancements of Components/Technology Protective Relaying • Electromechanical Relays – Solid State Relays • Solid State Relays – Microprocessor Relays Communications • Copper • Analog Microwave • Digital Microwave • 900MHz – Licensed & Spread Spectrum/Unlicensed • Fiber • Discrete Analog  Digital Multiplexed  IP 40 Years of Service 1969 2009

11. BROADBAND CARRIER CLASS NETWORKS DS0-1 DS0-2 DS1-1 DS0-3 OC1-1 OC3-1 DS0-4 DS1-2 OC48-1 OC192 . . . OC12-1 DS1-3 OC1-2 OC3-2 DS0-24 OC12-2 OC48-2 DS1-4 OC1-3 OC3-3 . . . OC12-3 OC3-4 OC48-3 DS1-28 OC12-4 OC48-4 IMUX JMUX JUNGLEMUX EXPANDABLE TO OC48 BANDWIDTH TELECOMMUNICATIONS CIRCUIT HIERARCHY Phone lines per circuit type 1 24 672 2,016 8,064 32,256 129,024 oo DWDM

12. And Now… Smart Grid!

13. Effects of Smart Grid and Communications Technology • Higher density of low-signal voltage circuits (RS-232, RS-485) over copper in the control house • More fiber in the control house • More non-substation hardened devices entering the control house • IT-Telecom teams becoming more involved in substation control houses • Organizational awareness of substation environment vs data center/telecom room requirements 40 Years of Service 1969 2009

14. Users of Substation Information • System Operators • P&C Engineering • Asset Management • Customer Service Center • Field Maintenance Personnel (line trucks, P&C, substation, etc.) • Electric System Customers (indirectly) • Personnel Managers • Corporate Security (access management, surveillance) • IT-Security Cyber-Security Teams • Utility Interchange (Where Transmission Tammy draws the line…) • Others… 40 Years of Service 1969 2009

15. Substation Communications: Change Is Here Traditional • Telemetry  Watts, Vars, Volts, Amps • Status  Open, Closed, Major, Minor • Control  Open, Close, Raise, Lower • Voice • SCADA – Analog/4 Wire AC Data Present Day • All of the above, plus • Temperature  Outdoor Ambient, Control House • Transformer Telemetry  Winding Temps, Dissolved Gas, Tap Position • Battery Voltage • IP Services • Security  Surveillance, Door Access Control • High Speed Remote Access for IEDs • Syncrophasors • Local Employee LAN Access • SCADA 40 Years of Service 1969 2009

16. “Change Is Here” • Increased data flow (to 27 TB/day or higher in larger utility systems) from substations • Not just SCADA • Non-Traditional organizations using or managing substation systems and information • Increased deployment of non-station hardened equipment, despite efforts by IEEE to develop standards such as IEEE-1613 40 Years of Service 1969 2009

17. PART 2: NAVIGATING THE TRANSITION • GOALS OF GROUNDING/BONDING – SUBSTATION AND TELECOM • BASICS AND DEFINITIONS • REAL WORLD CASE STUDY

18. Grounding and Bonding Basics Substation Goals Safety • Step and Touch • Ground Potential Rise Reliability • Lightning Mast/Shielding • Minimize Electrical System Damage and Outages • Lightning/Transient Suppression Equipment • Equalize potential differences across the station grid & in the control building • Systems redundancy emphasized on Bulk Power and system-significant generation 40 Years of Service 1969 2009

19. Grounding and Bonding Basics Telecommunications Goals Safety • Bonding of metallic components Reliability • Lightning protection and mitigation – outdoor • Single Point Ground Location for all attachments (Main Ground Bus) • Minimize equipment damage • Minimize telecom circuit outage time • Equipment and systems redundancy emphasized on Broadband • Reduce electrical noise • Reference for DC voltage 40 Years of Service 1969 2009

20. Substation Grounding – A Great Start! All outdoor metallic components are bonded to earth ground • Breakers • Transformers • Structures • Static Wires/OPGW • Distribution Neutrals • Station Service • Lightning Shielding (masts, overhead shield wires, etc.) Control House • 4/0 copper grounding conductors brought in from grid (multiple places typically) CAUTION!!! • 4/0 conductors snaked through cable trench/cable tray system, reduced to AWG #6 as needed for rack/panel connection • Relay/Metering/Control Panels tied to bond ‘snake’ running through the trench or tray cable management system 40 Years of Service 1969 2009

21. ANSI/IEEE Substation Grounding Standards IEEE 80: Guide for Safety in AC Substation Grounding Technical Target: Outdoor AC substations Purpose: • Establish safe limits of potential differences – human body interface • Substation grounding practices review for safety/safe design practices • Provide a procedure for the design of practical grounding systems based on the above • Develop analytical methods to aid in the understanding of gradient problems DOES NOT PROVIDE GUIDANCE FOR TELECOM RELIABILITY!!! 40 Years of Service 1969 2009

22. Telecom – Friendly Aspects of IEEE 80 Core benefits of an IEEE 80 ground grid design for Telecommunications • Excellent low net ground grid resistance, ½ ohm is possible, depending on final design • Site – specific ground grid design • Human – safe design, from a step-and-touch perspective • Ground Potential Rise voltage is typically limited and affected by step-and-touch design criteria 40 Years of Service 1969 2009

23. Grounding and Bonding Goals For Telecom • Safety – minimize potential differences between metallic paths • Reliability – ensure proper comm circuit operation despite transient conditions • Eliminate ground loops • Establish single point ground reference point in any one defined area (such as a control building room) • Provide an engineered design for grounding and bonding in an area with telecom equipment 40 Years of Service 1969 2009

24. Fundamental Differences Between Substation & Telecom Grounding (Control House) SUBSTATION • Not engineered by site, considered a ‘standard’ practice. • Grounding conductors can enter the control house in multiple locations and are tied to the station ground grid at different points • Racks bolted directly to the floor and to each other • Floating DC • Floor materials vary • No minimum ground/bond conductor radius typically specified TELECOM SITE • Engineered on a site basis (can be templatized) • Single point connection to ground field • Racks are isolated from the floor and from each other • DC (+) is grounded • Floor materials are conductive/anti-static • Minimum Bend Radius Specified for transient flow 40 Years of Service 1969 2009

25. Telecom Grounding & Bonding Definitions • “Grounding” – providing an engineered, low impedance path to earth • “Bonding” – the permanent joining of metallic parts to form an electrically conductive path which will assure electrical continuity and the capacity to safely conduct any current likely to be imposed, including 60Hz and transients • Grounded Conductor – a system or circuit conductor that is intentionally grounded (these normally carry current) • Example: Electrical neutral wire, the DC (+) cable in 48 V DC Telecom supplies • Grounding Conductor – a conductor used to connect equipment or the grounded circuit of a wiring system to a grounding electrode or electrodes (these do not normally carry current) • Example: AC Circuit electrical ground wire (the green wire), grounding wires used to interconnect racks, equipment bonding jumpers 40 Years of Service 1969 2009

26. Telecom Grounding & Bonding Definitions (cont’d) Solid Ground – an intentional connection to a grounding system, using a grounding wire in which there is no additional impedance imposed Incidental Ground – an unplanned grounding connection. Example – a conductive cabinet attached to a concrete surface via Tapcon screws can be said to be ‘Incidentally Grounded’ Earthing Electrode – a copper or copper-clad steel rod driven into the earth to provide a lower impedance path to true earth ground. Other types of earthing electrodes are steel well casings, structural steel ground grids, metallic piping for water, sewer, etc. True Earth Ground – a virtual location beneath the earth’s surface, where electrical resistance and impedance is zero, and ‘ground’ currents run freely, whether man-made or natural Skin Depth – a frequency and materials dependent calculation which determines the penetration of current flow density into the surface of a conductor. http://www.microwaves101.com/encyclopedia/calsdepth.cfm 40 Years of Service 1969 2009

27. Telecom Grounding & Bonding Components of a Telecom Grounding & Bonding System at a Substation CHPGP: Control House Principal Ground Point A ground bus bar located near the cable connection to the substation ground grid. It serves as the central connection point for all main grounding conductors and earthing electrode Horizontal Equalizer An insulated grounding conductor which has it’s origination point at the CHPGP, with the function of connecting conductive equipment in a home run fashion to the principal grounding point in the room Halo Ground A grounding conductor, supported on insulated stand-offs around the perimeter of the room, typically installed at seven feet or higher elevation, to which all peripheral equipment are bonded (HVAC, Heaters, Junction Boxes, etc.). The Halo is a radial connection, and not a complete electrical loop. Mechanical and Exothermic Connections Cable-to-device or cable-cable connections. Outdoor connections are typically exothermic, in-building connections are typically mechanical compression, with two-hole lugs. Hardware & Miscellaneous Insulated stand offs, cable management, plexiglas or Lexan shields, stainless steel nuts & bolts, no-oxide grease, exothermic weld molds, mechanical connectors, etc. 40 Years of Service 1969 2009

28. Case Study: Wind Farm Control House Application Attributes: • Collector Station (34kV-230kV) yard adjacent to transmission switching station • Transmission switching station has microwave tower for Primary relaying channel, SCADA, and internal voice communications • Copper leased entrance cable, with isolation, at Transmission control house • Transmission control house has “PRIMARY” and “SECONDARY” rooms • Communications racks and telco isolation equipment in PRIMARY room • PA System in place to cover the switchyard (copper connections to yard corners) 40 Years of Service 1969 2009

29. Grounding-BondingCommunications Tower & Outside Facilities • Wireless communications for Smart Grid • Requires lightning protection @ top • Proper bonding along feedline route • Bond @ antenna • Bond prior to horizontal transition • Bond prior to CH entry • Center conductor protection just inside CH • Driven rods @ tower & feedline entrance 40 Years of Service 1969 2009 STATION GROUND GRID

30. Case Study Substation

31. Overall Communications Elementary

32. Control House Floor Plan

33. Ice Bridge Detail 40 Years of Service 1969 2009

34. 40 Years of Service 1969 2009 Inside Wall Elevation

35. Cross Section Elevation 40 Years of Service 1969 2009

36. Control House Bonding Connections

37. Grounding-Bonding Inside The Control House • Key Design Features: • Single Point Ground Bus (no ground loops) • Discrete (insulated preferred) home-run bonding connections to all equipment connections: • Cable tray & rack taps • AC System Neutral @ AC Panel • Telecom Reference Ground point • Substation ground grid connection • Building steel • Microwave feedlines • Departure From Telecom Practice • Racks directly bolted to floor and each other without isolation • Cable trays may not be bonded across joints • Grounding conductors not insulated 40 Years of Service 1969 2009

38. A Few Images…

39. SCADA “Master” 900 MHz Transceiver 900 MHz SCADA “Remote” 900 MHz Transceiver – Indoor Mount

40. “Smart” Recloser “Master” Tower

41. Tower Leg Bonding

43. Simple Feedline Entrance Halo Ground

44. Outdoor Main Ground Bus Mounting Insulated Stand-Off

45. Feedline Entrance

46. Ground Bus Bar Example

47. Main Ground Bus…“Producers” and “Absorbers” SeparatedClear separation of power, grounding, and data cables

48. DC (+) Ground Reference…

49. “A” and “B” Battery Strings Separately Grounded

50. Isolation pads under rackAnti-Static floor tiles