Solar Electric PV Systems design and the 2015 Electrical Code ED KNAGGS HES PV eknaggs@hespv.com
Canada s largest PV System Designer and Equipment Distributor Over 25 years of PV System Experience l
HISTORY OF SOLAR ELECTRICITY (Photovoltaics) 1954 - On April 25, Bell Labs announces the invention of the first practical silicon solar cell. [3][4] Shortly afterwards, they are shown at the National Academy of Science Meeting. These cells have about 3-6% efficiency.
History of PV 1986-1996 10% 1996 50W $700 $12/W SOURCE: SPV MARKET RESEARCH
History of PV 1996-2006 15% 2005 100W $700 $7/W 1999: 1GW Total Installed Capacity SOURCE: SPV MARKET RESEARCH
History of PV 2006-2013 50% Growth Rate 2013 250W $344 $1.38/W 24% Efficiency is a reality SOURCE: SPV MARKET RESEARCH
Future World Solar Market 2012 Totals World -24,263 MW Canada 208 MW 2014 Totals World -39,918 MW Canada 400 MW? 2013 Totals World -33403 MW Canada-334MW 2017 Totals World -35,954MW Canada 200MW? 2008 Totals World -5,491 MW 2010 Totals World -17,402 MW Canada 187 MW Source: SPV MARKETING
Solar PV Growth in BC # cust kw 500 2500 400 2000 300 1500 200 1000 100 500 0 2004 2006 2008 2010 2012 2014 0 Year # of customers capacity, kw 8
PV prices have dropped over 85% 2005-160W - $1,555- $9.71/W 2011-225W - $807 - $3.58/W 2014 265W-$357 - $1.35/W
NET METERING Load Tie (Series) STANDING OFFER Line Tie (Parallel) Solar Modules Strings Utility System 120/240V Utility System 120/240V Solar Modules Strings Combiner box System Disconnect Utility Meter Main Panel Combiner box System Disconnect PV Meter Utility Meter Inverter w DC Disconnect Main Panel Inverter w DC Disconnect
Net Metering -Reducing the Load 200W 500W 700W
Net Metering Outflow Credit 2000W 1300W 700W
System Design - How much Power can your roof produce? 10W/SF Sloped roof 1 60 cell Solar Module = 250W-275W 5W/SF Flat roof
System Design Estimate Array size Area 1 100x85x5= 42,500w Area 2-80x30x5= 12,000w Area 3 145x105x5= 76,125w Total = 130,625w
64-114 (2012) or 64-112 (2015)C&D Sum of the breakers feeding the buss cannot exceed the buss rating by 1.2 times or 1.25 times for a dwelling. BUSS, 800A, 208V 64-112 DO NOT RELOCATE BREAKER, 800A, 208V 800A Buss x 1.2 = 960 800A Breaker = 160A Approx 58,000w
System Design Final Array layout Electrical Room, DC and AC wire runs Structural issues, obstructions and shading 35kW Budget = $3-4/w = $105k
SHADING & ROW SPACING Winter Sun Angle is roughly 20 Degrees for a Latitude of 50N Spacing (S) = Height (H)/Tan 20 Where (H) = Sin 25(tilt angle) x Panel Length (PL) SNOW?
PV Potential Factors TOTAL LOSSES FROM PV TO GRID ROUGHLY 12% Location Tilt & Azimuth Shading & Diffusion Soiling (snow) Temperature Reflectance Degradation Cable and Inverter
PV Potential -1150 kwh/kw SOFTWARE PVSYST PVWATTS RETSCREEN 35kW x 1150 kwh/kw/year = 40,250 kwh/year 35 Degree Tilt, Facing Due South with No Shading Source; NRCAN
ELECTRICAL CODE Applicable Section of the Code. Section 50 Solar photovoltaic systems. Now 64-2XX Section 64 Renewable energy systems. (except Class 2 circuits) Section 84 Interconnection of electric power production sources. Other general sections such as those that address conductor ampacites, grounding and bonding and wiring methods still apply. Being adopted with an effective date of Jan 2016.
2015 Electrical safety Code Changes/additions to existing rules include: Definitions & Marking System Bonding & Grounding Application Class New Rules and requirements: DC Ground Fault Disconnecting Combiners AFCI now includes ground mounts Rapid Shut-down 1000V dc systems Conductor colour coding
Terminology
Approval. The inverter must be a certified product. CSA 22.2 107.1 IEC62109-1-2 (coming soon) In addition the inverters must be approved for their intended use. i.e. Utility interactive. Grounded or ungrounded dc systems. The type of ac system they are feeding Solar Module must meet CSA22.2 61730-1-2 or ULC/ORD-C1703-01
64-072, 64-074,64-112,64-200, 84-024, 84-030 RED LABEL WITH WHITE LETTERS Marking & warning labels DIAGRAM, RAPID SHUTDOWN, WARNINGS 64-200 UNGROUNDED 64-072 INVERTER AC OUTPUT 64-112 DO NOT RELOCATE
Marking & warning labels Cont d Where multiple sources exist warning labels and or drawings shall indicate the presence and location of each source. 64-074 System diagram. Notice of rapid shut down location. Warning notice if a storage device is installed. DC disc. A label listing. Rated operating current & voltage, Maximum PV source circuit voltage. Rated short circuit current.
64-202 Voltage of solar photovoltaic systems Old Rule 50-004(b) required marking of the rated open-circuit voltage of the PV output circuit at the disconnecting location. New rule requires Maximum Source Circuit Voltage The rule has been amended to allow you to calculate the Maximum Source Circuit Voltage by multiplying the systems rated open circuit voltage by 125% or by using the open circuit voltage, local lowest minimum daily temperature and the manufactures temperature coefficient.
Effect of Temperature on Solar Panel Output Panels are rated at 25 o C Panel Voltage drops with increase temperatures Panel Voltage Increases with decrease temperatures Design for worst case -40 to +40 degrees A panel rated at Voc=44.4 will actually produce a Voc=54.15V at -40 degrees Voc=44.4V (at STC 25 o C) Temp coef = -0.36%/ o C V(t) =Voc(25 o C) +0.15V/ o C V(t) = 44.4Voc + 0.15Vx(25-(-40)) V(t) = 44.4Voc + 9.75V V(t)=54.15V (at -40 o C)
64-202 Allowed Voltage of PV Systems Dwellings are limited to 600V dc. PV source and output circuits between 750 and 1000V dc. (exempt from HV circuit protection and disconnecting rules) A 1000V rated inverter can be used on a dwelling if the PV source and outputs are limited to 600V
64-216 Arc-fault protection for d/c circuits D/C arc-fault or equivalent protection is required for all D/C source or output circuits operating at 80 volts or greater that are located on or penetrate a building. It is still not possible to comply with this rule for OFF-GRID installations. 600Vdc ARC
64-218 PV system rapid shutdown Applies to systems installed on buildings or structures where the PV output conductors are more than 1.5 m in length or more than 3m from a PV array. Shall limit PV source or output circuits to not more than 30 V and 240 V A within 10 s of rapid shutdown initiation.
64-110 Unbalanced interconnections It is permitted provided: They have a balanced 3-phase output. Disconnects on loss of power of any phase (phase loss). Approved by supply authority. Approved for 3-phase use. PHASE LOSS DEVICE
64-212 Conductor colour coding (a) for a 2-wire circuit red for positive and black for negative; and (b) for a 3-wire circuit (bipolar circuit) white, grey, or white with a coloured stripe for mid-wire (identified as the centre tap), red for positive, and black for negative; 32
Wiring Methods 64-212 Within an array Protection of conductors. Open conductors subject to damage during or after installation require mechanical protection. greater than 30V where the array is not installed in readily accessible locations. Cables & conductors shall be supported as per Section 12. (Within 300mm of each box & 1.5m thereafter. See Bulletin 50-1-).
64-206 Current Rating Current rating of photovoltaic source circuits When determining the current rating the PV circuit, the rating of the over current device, or ampacity of conductors is used (whichever is less), and neither can be less than the rated short circuit current of the PV x 1.25. HES250 =8.59A x 1.25 = 10.74A 34
64-214 Overcurrent protection of modules. Cont d Notwithstanding Rules 64-058(1) and 64-066(1)(a), individual overcurrent protection devices shall not be required where the sum of the available shortcircuit current is not greater than the rated ampacity of the apparatus or conductors
64-060(12) Combiner Box Disconnecting Means & warning labels Warning Multiple supply sources. Do Not Disconnect under load. Disconnect all sources before servicing. 36 It is intended that means will be provided to isolate and disable portions of an array or photovoltaic module that may require servicing. An opaque covering is an acceptable means of disabling the array.
64-222, 64-070 Bonding 64-064, 64-068 Grounding Utility System 120/240V Utility Meter Bonding refers to the provision of connections between metal non-current-carrying parts, with the intention that they all be maintained at a common voltage. Main Panel Combiner box BONDING CONDUCTOR BONDING & DC GROUNDING CONDUCTOR BONDING & DC GROUNDING CONDUCTOR Utility Disconnect Grounding refers to the provision of a metal or conducting path to a grounding electrode. Approved Inverter with GFP AC & DC System Ground Conductor
Module bonding Existing rule Rule 64-070 & 10-400 requires non-current-carrying metal parts of fixed electrical equipment to be bonded. The size of the conductor is dictated by Rule 10-814 & Table 16. Rule 64-222 requires the bonding to be installed in such a manner that the removal of a module will not interrupt the bonding to other equipment. NOT CORRECT
64-068 System Grounding 10-202 Grounding the DC system negative should be done at one point only. (the system supply). This is done inside the GT inverter s GFI. 84-028 The service ground can be used as the system ground. 10-810 The system ground for PV needs to be sized in accordance with 10-812 AC ground #6
Solar PV system grounding. (Rule 50-026, 64-018, 10-810) Rule 50-026 requires the system to be grounded as per Rule 64-016. Rule 10-810 has been amended to allow the dc grounding conductor for PV systems to be #6 copper. Diagram 1
Solar PV system grounding. (Rule 50-026, 64-018, 10-810) Diagram 2 Diagram 3
Solar PV system grounding. (Rule 50-026, 64-018, 10-810) DC systems are permitted to be ungrounded provided: All conductors have overcurrent protection Conductors are in metallic raceways or metal-sheathed cables. Warning signs at all disconnects, devices and junction boxes. Inverts and charge controllers(if used) shall be approved for ungrounded systems. TRANSFORMERLESS The system shall be ground fault protected. FUSE THE POS AND NEG CONDUCTORS WARNING: UNGROUNDED CONDUCTORS
64-208 PV Module application Class Application Class A photovoltaic module an unrestricted access module approved and marked for use in solar photovoltaic systems operating in excess of 50 V dc or in excess of 240 W. Application Class B photovoltaic module a restricted access module approved and marked for use in solar photovoltaic systems where the module is inaccessible to the public. (Behind the Fence) Application Class C photovoltaic module a limited voltage, unrestricted access module, approved and marked for use in photovoltaic systems operating at 50 V dc or less and 240 W or less. For the application of this Rule, approved modules without an application class marking are considered to be application Class A 43
64-208 PV Module application Class Photovoltaic modules marked with application Class A or C shall be permitted to be installed in a location accessible to the public. Photovoltaic modules marked with an application Class B shall not be permitted for installations accessible to the public. located within a fenced enclosure, guarded by locked doors, elevated 3 m or more above grade level or above any surface that a person can stand on, or where access is restricted by other effective means. 44
64-064 (4) Ground Fault Protection Above 50V dc requires a GFP device. 45
64-114 (2012) or 64-112 (2015)C&D INTERACTIVE INVERTER POINT OF CONNECTION Example1: In a residential dwelling a main panel has a busbar rating of 200Amps and a main breaker rating of 200Amps. The maximum solar breaker allowed would be (busbar x 1.25) 250A - 200A (main breaker) = 50A solar breaker. Example2: In a residential dwelling a main panel has a busbar rating of 225Amps and a main breaker rating of 200Amps. The maximum solar breaker allowed would be (busbar x 1.25) 281A - 200A (main breaker) = 80A solar breaker. 46