A structured safety and maintenance schedule for new solar plant critical equipment (HT Panels, Inverter Duty Transformers, ACDB, and UPS) is crucial for longevity and safety, typically involving daily monitoring, monthly inspections, and quarterly or annual shutdowns. 

Ensuring the safety and accuracy of meteorological monitoring systems (WMS)—specifically pyranometers, anemometers, and rain sensors—is critical for calculating the Performance Ratio (PR) and ensuring the long-term reliability of a new solar plant. Proper safety protocols and maintenance prevent data inaccuracy and hazardous situations during maintenance. 

Critical Equipment Maintenance Schedule

1. HT Panel (High Tension/Voltage Panel) 

Daily: Check indicating lamps, monitor HV panel meters (current, voltage), and check for unusual sounds or odors.

Monthly: Visually inspect for cleanliness, dust accumulation, and signs of corrosion.

Quarterly/Shutdown:

Tightness: Check and tighten all power cable connections, bus bars, and control wiring to prevent overheating.

Cleaning: Use a vacuum/blower to clean dust from the breaker and control chamber.

Breaker Test: Perform maintenance on the HT breaker (e.g., rack out, discharge springs, check operating mechanisms).

Insulation Resistance (IR): Measure IR values of poles and to earth.

2. IDT (Inverter Duty Transformer)

Daily: Check oil levels in the conservator, monitor winding temperature, and check for oil leaks.

Monthly: Clean bushings and inspect for cracks or dirt.

Quarterly/Half-Yearly:

Oil Testing: Perform Dielectric Strength (BDV) tests on transformer oil.

Silica Gel: Check the silica gel color (replace if pink).

Tightness: Inspect HV/LV terminations and tighten connections.

Earthing: Verify body and neutral earthing connections.

3. ACDB (AC Distribution Board)

Daily: Check status of incoming and outgoing MCCBs/MCBs.

Monthly: Visual inspection for signs of overheating (discoloration of plastic or cables).

Quarterly:

Tightness: Tighten all cable terminations and bus bar joints.

Functionality: Test operation of MCCBs, MCBs, and surge protection devices (SPDs).

Cleaning: Clean the internal components using a dry cloth or vacuum cleaner. 

4. UPS (Uninterruptible Power Supply)

Daily: Check front panel indicators for alarm status.

Monthly: Ensure proper ventilation and check fans are functioning.

Quarterly/Half-Yearly:

Battery Check: Measure terminal voltage of the battery bank and check for terminal tightness/corrosion.

Cleaning: Clean internal components (dust can cause overheating).

Backup Test: Perform a discharge test on the battery to check for functionality. 

General Safety and Maintenance Measures

Thermal Imaging: Conduct thermal imaging scanning on all electrical panels (HT, ACDB) quarterly to identify hotspots caused by loose connections or overloading.

Earthing System: Test earthing resistance at all major equipment annually (should be <2 ohms).

Safety Protocols: Always use personal protective equipment (PPE) and follow Lockout/Tagout (LOTO) procedures when performing maintenance. 

Critical Equipment Safety & Maintenance Schedule

1. Pyranometer (Solar Irradiation) 

Daily Safety/Maintenance: Visually inspect for cleanliness, debris, or bird droppings. Wipe the glass dome gently with a microfiber cloth.

Monthly Maintenance: Check the desiccant color in the dryer cartridge (if it changes from orange to dark, replace it). Check the leveling and orientation.

Every 2 Years: Re-calibrate the sensor to maintain ISO/WMO standards (secondary standard, first-class).

Safety Note: Do not disassemble the glass dome. 

2. Anemometer (Wind Speed & Direction)

Daily/Weekly Inspection: Inspect for any structural damage to the cups or propeller.

Quarterly Maintenance: Check for proper functioning of moving parts; ensure the anemometer rotates freely without resistance.

Safety Note: Prohibit use in flammable environments. Shut down immediately if it emits abnormal smell, sound, or smoke.

3. Rain Sensor (Rainfall)

Monthly Maintenance: Check the rain gauge for debris or mud blockage to ensure accurate measurement.

Quarterly Maintenance: Verify the connection to the data logger.

Safety Note: Clean with soft cloth only, not abrasive materials. 

General WMS & Site Safety

Safety Gear (PPE): Technicians must wear safety glasses, hard hats, gloves, and protective clothing during all maintenance.

Working at Height: Use proper fall protection (harnesses) when accessing sensors installed on masts or high rooftops.

Electrical Safety: Ensure that all sensor maintenance is done using insulated tools and that no electrical components are exposed.

Lightning Protection: Ensure the meteorological station has proper earthing and lightning protection to prevent damage during storms.

Key Performance Indicators (Safety/Accuracy)

High PR Ratio (>85%): An abnormally high PR can indicate that the pyranometer is dirty, misaligned, or incorrectly recording radiation.

Consistency Check: Compare wind and rain data against regional weather reports to verify sensor reliability. 

This schedule should be adapted based on the specific manufacturer's recommendations and the environmental conditions at your site.