Best Electrical Safety For Solar/PV System

BEST ELECTRICAL SAFETY FOR SOLAR/PV SYSTEM

Class Goals & Objectives

1. Review the purpose of Grounding & Bonding in PV systems 2. Evaluate the proper methods to install Grounding & Bonding System 3. Complete designing of PV Earthing & Bonding 4. ESE Lightning Protection

5. Surge Protection Devices

Solar In India

The Indian government has launched Jawaharlal Nehru National Solar Mission (JNNSM) with a target of achieving 20000 MW by 2022. The goal is to make India one of the leaders in solar energy.

So it is important to investigate the performance of solar power plants.

There are various factors contributing to the performance of solar power plants: such as radiation, temperature and other climatic conditions, design criteria for better performance of power plants, inverter efficiency Earthing, lightning & surge protection system designing and degradation due to aging.

Ground - the earth

Bonding - connected to establish electrical continuity & conductivity

Prime Objective Of Earthing

Provide a Zero Potential Surface

Prevent or at least Minimize Damage Improve the reliability of Power Supply Ensures Public Safety, as well as

Safety of PV Installers and Field Electricians

PV Plant Earthing has divided into Four categories, follows as:

I) DC Earthing: PV Panel is the main generation source for the PV Plant. DC Part also covers MMS [Module Mounting Structure], SMB [String Monitoring Box].

II) AC Earthing: This Part Covers Inverter, Transformer, HT Panels, LT Distribution system Reserved for Auxiliary distribution, Power Evacuation system.

III) Special Earthing: This Part Covers SCADA, UPS, CCTV etc.

IV) AC EHV [Extra High Voltage] Earthing: This is mainly needed for large scale PV Power Plants which Permits Switchyard generally needed for the Plant Capacity exceeds 5MW.

Present Earthing Practice In solar Industry

1. Electrode Earthing -Hollow pipe or pipe with internal strip - Dia. 40, 50mm, 76mm, 88 mm - Pipe thickness 2 mm to 4.3 mm - Crystalline conductive mixture - Galvanized iron pipe - Welding at the corners

2. GI Strips for DC - 25X3 mm - 25x6 mm

3. Electrical Connections -NUT & Bolt -Welding

Defects in Electrode Technology

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Only complying IS 3043, does not recommended internationally

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Manufacturing defects -Length of internal pipe/strip -Clay or sand in place of CCM -Welding for closing electrode -Micron coating should be 80-100

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Salt dissolves in water and conductivity dips over time thereby increasing the resistance

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The backfill (SALT) reacts with the electrode and causes corrosion

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Low Price, Less Life, Poor Quality & Degraded Performance

Performance Status of Present Earthing Practice

-Because of Poor Quality Earthing, many PV Installation meets: - poor grounding connectivity - increase in resistance value - poor performance - totally ineffective earthing - Due to underground corrosion, earthing system life will get minimized -When we done poor quality earthing, life of the PV Panels will get reduced.

- Failure of the entire PV system results in Generation Loss -Maintenance Cost Increases

Best Earthing Practices to enhance PV System Performance

Copper Bonded Rod

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Complying standards IEC 62561, IEEE 80, NBC 2016, UL 467, IS 3043

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Offers 4 to 5 times more working life than GI electrode

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Excellent fault current carrying capacity

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Exhibits same corrosion resistant property as copper

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High strength of steel

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A cost effective solution

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Theft proof solution……. WHY?

Reducing Earthing Theft with Copper Bonded and Copper Clad Material

Thief

Traders

Big Traders

Factory

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Because it cannot be re-cycled or re-consumed

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Solid low carbon steel (1018 grade) core and molecularly bonded with a minimum of 250µm copper.

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Zero scrap value

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Steel & copper cannot be separated by any melting process

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As melting temperature of copper is 1,085 °C and steel melts at 1,427 °C .

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Cannot be removed from the grounding system using normal copper cutting hand tools

NEGRP-Research on the Service Life of Grounding Rod National Electrical Grounding Research Project (NEGRP) Conducted by NFPA Several different types of earthing rods were buried in different types of soils at various sites After 10 years in 2003, one of the original sites (Pawnee, US) was excavated galvanized rod showed significant deterioration Whereas, UL listed copper bonded rod was virtually free of corrosion providing a 40+ year life, typically 4 times that of galvanized ground rod.

Testing on Copper Bonded R as per UL 467

•Adherence to Coating Test •Bending Test

•Thickness of Protective Coating Test •Salt spray Test for Corrosion

* This is how we can ensure the quality of copper bonded rod and these tests has been perform for every lot in our factory as UL 467.

Role of an Earth Enhancement Compound

Conforms to IEC 62561-7, IEEE 80

Low-resistance, non-corrosive, carbon-based superior conductive material

Does not dissolve, decompose or leach out with time Conforms Corrosion, leaching, sulfur content, and other environmental regulations

Improves grounding effectiveness, especially in areas of poor conductivity

Suitable for limited land areas where grounding is difficult with conventional methods

Maintenance free solution

Does not contain any hazardous component complying RoHS

Copper Clad Steel ConductorBest Replacement of GI Strip •

Complying standards IEEE 80, ASTM B228, ASTM B227, IS 3043 also mentioned round conductor

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Cost effective replacement of solid copper conductor/ GI Strips

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High current carrying capacity contrasted with most metals

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Offers better electrical conductivity

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Life is 4 to 5 times more than GI Strip/ flats.

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A cost effective solution

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Theft proof solution

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Easy to install, hard to damage

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Reduces the number of joints

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Zero Scrap Value

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8mm dia & 6 mm dia conductor is best for DC Earthing

Earthing Connections & Joint Practices

For making earthing connections & electrical jointing, mechanical joints are still prevails.

Nut & Bolt, welding, clamping, brazing Only give 8-20% contact surface area Gets corroded over the period of time due to atmospheric corrosion Contact areas of connections have voids and gaps which cause corrosion, rust and oxide results in early deterioration Resistance of mechanical connections increases with time and this alters the conductive properties of connections

Exothermic Welding SystemAn Advance Technology

Exothermic Welding Mould

These cavity can be designed on customize basis as per the type of joint is required.

Also the dimension of the conductors which needs to be joint in a kind of jointing.

We are the manufacturer and can offer any kind of joint type as mentioned below:

SOLAR/PV SYSTEM LIGHTNING PROTECTION - Conventional Lightning Protection as per IS/IEC 62305 - ESE Lightning Protection as per NF C 17-102 - Surge Protection Devices

Need of Lightning Protection

Lightning is a common cause of failures in photovoltaic (PV) systems.

• • • •

A strike can average 100 million volts of electricity Current of up to 200,000 amperes Can generate 54,000 oF 10/350MicroSec/50KA Fault Current/Discharge in Nano Sec

Solar systems are often installed in open spaces, away from tall structures, and therefore they are more prone to lightning strikes and associated damage.

Studies indicate that lightning is the number one cause of catastrophic failures for roof top as well as ground mounted PV system.

Also high voltage surges or transient currents, caused by invisible strikes at a large distance from the solar system, may cause damage.

Lightning Protection As Per IS/IEC 62305

Protection Angle method using vertical rod is the best suited method for up to 25 kw projects. Later, shadow as well as installation will be an issue.

Lightning Protection As Per NF C 17 102

ESE Lightning Protection •An active and advance technology device based on the principle of Corona effect.

•Internationally accepted technology complying standard NFC 17-102.

•Active Protection not only protects the structure also protect surroundings & open areas.

•Made up of stainless steel SS-316L hence highly corrosion resistant and long lasting.

•More life due to corrosion resistant material is used.

•Single installation offering maximum radius of protection of 109 meters which is very large in comparison to conventional lightning system.

•ESE air terminal is very quick in response.

•Excellent, no electronic device.

•Economical solution.

•Easy to Install.

Safety Main It Should be Remain (Protect your Equipment for Internal & External Surges)

The 100% of lightning energy breaks down as follows: a) 50% of the lightning current will flow through the ground

b) 50% of the lightning current will flow over the

connected metal parts out of the building: • about 10% to the water pipe (metal) • about 10% to the gas pipe (metal) • about 10% to the oil pipe (metal tank) • about 10% to the sewage pipe

• about 10% to the power supplier’s incoming feed • max. 5% or 5 kA shared across all data lines

Reasons of Surge Generation

Basic Principle of Surge Generation

Complying Standard

Solar Surge Protection Solution

JMV is offering Best Designing Solution for Earthing/ Lightning/ Surge Protection

We are designing complete solar earthing including DC & AC side.

Complying IEEE-80 for switchyard designing.

We are expertise in designing KW & MW projects latest by 140 MW. With in house designing team, we incorporate every latest & technically advanced technologies to enhance the life of PV Earthing System as well as PV Plant.

We ensure complete electrical safety with earthing & lightning protection.

THANK YOU