Safety Devices for HT Line & HT-Evacuated Solar Power Plant (Simplified & Detailed Guide)
In any HT (High Tension) evacuation system of a solar power plant, safety devices are not optional — they are essential for protecting transformers, cables, switchgear, and most importantly, human life.
Below is a simplified yet detailed explanation of the most critical safety devices, their importance, and correct usage.
1️⃣ Lightning Arrester (LA)
๐น Importance
Protects HT transformers, VCB panels, and cables from lightning surges and switching surges
Prevents insulation breakdown and transformer failure
Avoids costly equipment damage and plant shutdown
Acts as the first line of defense against overvoltage
When lightning strikes or a switching surge occurs, the arrester safely diverts the excess voltage to earth.
๐น How to Use
Install at:
HT line entry point
Near transformer HT side
Ensure dedicated and low-resistance earthing
Keep earth lead as short and straight as possible
Inspect periodically for:
Cracks
Leakage marks
Bulging or discoloration
Check earth connection tightness during maintenance
2️⃣ Vacuum Circuit Breaker (VCB)
๐น Importance
Trips during:
Overcurrent (OC)
Short circuit
Earth fault (EF)
Voltage abnormalities
Instantly isolates faulty section
Prevents fire, transformer damage, and cable burning
Essential for HT system protection
The VCB works as the main protective switching device in HT systems.
๐น How to Use
Set protection relays properly (OC, EF, UV, OV)
Perform relay injection testing before energizing
Never bypass trip circuits
Ensure mechanical & electrical interlocks are functional
Perform periodic maintenance & contact wear inspection
3️⃣ Protective Relays (OC / EF / UV / OV)
๐น Importance
Continuously monitors system conditions
Detects abnormal situations like:
Overcurrent (OC)
Earth fault (EF)
Under-voltage (UV)
Over-voltage (OV)
Sends trip signal to VCB
Prevents transformer burning & cable failure
Relays are the brain of the protection system.
๐น How to Use
Set parameters as per:
Transformer capacity
Cable rating
DISCOM requirement
Conduct annual testing & calibration
Perform secondary injection test before commissioning
Record all relay settings in documentation
Seal relay settings after final approval
4️⃣ Earthing System
๐น Importance
Safely carries fault current to ground
Protects manpower from electric shock
Reduces step & touch potential
Maintains system stability during faults
Critical for lightning protection effectiveness
Without proper earthing, no protection system works effectively.
๐น How to Use
Maintain earth resistance within permissible limits (as per IS/IEC & DISCOM)
Provide:
Separate equipment earthing
Separate body earthing
Dedicated LA earthing
Use proper size GI/CI strips
Perform periodic earth resistance testing
Maintain earth pit watering & inspection schedule
5️⃣ Ring Main Unit (RMU)
๐น Importance
Provides sectionalizing of HT network
Isolates faulty section without shutting entire plant
Improves supply reliability
Enables safe maintenance
Required for many DISCOM-connected systems
RMU increases system flexibility and reliability.
๐น How to Use
Follow proper switching sequence
Ensure mechanical interlocks are working
Confirm breaker open before earth switch operation
Never operate without proper SOP & authorization
Display mimic diagram clearly on panel
๐ Why These Safety Devices Are Critical
✔ Prevent transformer explosion
✔ Avoid cable failure
✔ Protect human life
✔ Ensure DISCOM compliance
✔ Reduce downtime & revenue loss
✔ Increase plant reliability
⚠ Golden Rules for HT Safety
❌ Never perform live HT work
๐ Follow LOTO (Lockout/Tagout) strictly
๐ท Only trained & authorized manpower allowed
๐ Confirm earthing continuity before charging
๐ Always follow approved SOP
๐งช Mandatory Pre-Commissioning Tests
Before energizing HT system, perform:
IR (Insulation Resistance) Test
HV Pressure / Hi-Pot Test
Transformer Ratio & Vector Group Test
Earthing Resistance Test
Relay Testing (Secondary Injection)
VCB Functional Test
Cable Continuity & Phasing Test
๐ Final Note
Pre-commissioning testing is the final safety and quality checkpoint before giving life to the HT system.
A properly protected HT evacuation system ensures:
Long transformer life
Safe plant operation
Zero major accidents
Stable revenue generation
If you want, I can convert this into:
https://www.youtube.com/channel/UC4_D50vMu1wbQrPaLFYo6Eg https://www.youtube.com/channel/UC4_D50vMu1wbQrPaLFYo6Eg RRB JE, SSC AE/JE UPSSSC JE, SSC JE, CIVIL ENGINEERING MCQs, ELECTICAL ENGINEERING MCQs, preavious year quesion papers, dmrc, lmrc, drdo,rrb ntpc, ntpc, pgcil, dsssb, states board, GATE IES EE, ESE, ECE, ME, CE, IT & CS EXAM MATERIALS & OLD PAPERS Electrical Engineering https://t.me/pravendrarajpoot Daily news & current affairs in hindi & english fully updated Daily current affairs https://t.me/newsdailypkr Engineering Discussion group for your upcoming exams, you can ask your any query regarding your problem,๐๐๐ https://t.me/joinchat/JObxeA7n6S4qvnegrGhTgA PKR ELECTRICAL ENGINEERING I am sure this is the best place for you guys subscribe and get success IF YOU WANT TO JOIN ME ON TELEGRAM FOR PDF @newsdailypkr AE/JE EE, ESE, ECE, ME, CE, IT & CS EXAM MATERIALS & OLD PAPERS Electrical Engineering https://t.me/pravendrarajpoot facebook page:- Pravendra Kumar Rajpoot https://t.me/newsdailypkr https://chat.whatsapp.com/5AS7dNFTP4H4vVsiWsqHrT https://t.me/srk50 https://t.me/pravendrarajpoot https://t.me/joinchat/JObxeA7n6S4qvnegrGhTgA https://t.me/pravendrarajpoot Daily news & current affairs in hindi & english fully updated Daily current affairs https://t.me/newsdailypkr Engineering Discussion group for your upcoming exams, you can ask your any query regarding your problem,๐๐๐ https://t.me/joinchat/JObxeA7n6S4qvnegrGhTgA PKR ELECTRICAL ENGINEERING I am sure this is the best place for you guys subscribe and get success IF YOU WANT TO JOIN ME ON TELEGRAM FOR PDF @newsdailypkr AE/JE EE, ESE, ECE, ME, CE, IT & CS EXAM MATERIALS & OLD PAPERS Electrical Engineering https://t.me/pravendrarajpoot facebook page:- Pravendra Kumar Rajpoot https://t.me/newsdailypkr https://chat.whatsapp.com/5AS7dNFTP4H4vVsiWsqHrT https://t.me/srk50 https://t.me/pravendrarajpoot https://t.me/joinchat/JObxeA7n6S4qvnegrGhTgA
No comments:
Post a Comment