MMS (Module Mounting Structure):
The rails, clamps, and foundations/ballast/piles that hold PV modules at the correct tilt and direction. It keeps panels secure under wind/snow loads, ensures alignment for best energy, and meets structural/safety codes essential for both rooftops and ground-mount sites.
String / Array / Block:
A string is modules in series; strings combine into an array; arrays feed an inverter block. This hierarchy drives electrical sizing, IV testing, labelling, isolation, and fault-finding in the field.
Inverter (String/Central):
Power electronics that convert DC→AC; string inverters are many small units near arrays, central are large block units. They perform MPPT, protections, and grid-quality output—core to commissioning, monitoring, and performance.
SPD / LA / Earthing:
Surge Protective Devices, Lightning Arresters, and the grounding network that shield equipment from surges, lightning, and faults. They’re mandatory for safety/uptime and referenced in CEA/BIS inspection checklists.
IV / EL — IV-Curve & Electroluminescence:
IV tests show electrical health of strings/modules; EL is a dark-room image revealing micro-cracks and cell defects. Both underpin acceptance testing, diagnostics, and warranty claims.
Torque / Insulation / Continuity / Polarity Tests:
Standard pre-energisation checks to confirm tight terminations, insulation resistance, conductor integrity, and correct polarity. They prevent hot-spots and nuisance trips and speed CEI/CEIG clearance.
PR / CUF — Performance Ratio / Capacity Utilisation Factor:
PR measures system efficiency independent of irradiance; CUF shows delivered energy vs nameplate over time. Together they’re headline KPIs for O&M SLAs and benchmarking.
CMMS — Computerised Maintenance Management System:
The ticket and history system for preventive/corrective maintenance, spares, and SLAs. It enforces discipline, reduces MTTR, preserves evidence, and makes audits straightforward.
SCADA / DAS / RTU:
Supervisory control & visualisation (SCADA), data acquisition (DAS), and field interface (RTU) that bring plant data to screens. They enable real-time alarms, KPI/energy reporting, remote resets, and reliable operations.
SLDC / ABT / DSM:
SLDC schedules and controls the state grid; ABT is the tariff framework; DSM settles deviations from schedule. Knowing these avoids penalties and keeps utility-scale plants compliant.
CEI/CEIG — Electrical Inspectorate:
Statutory authority reviewing documentation and inspecting plants before energisation. Their approvals are required for lawful commissioning and rely on test records, drawings, and safety logs.
CEA / BIS / IS / IEC — Rules & Standards:
CEA issues grid/safety regulations; BIS/IS are Indian standards; IEC are international references. Designers, EPCs, and inspectors rely on them for equipment choice and acceptance criteria.
PPA / CTU / STU / ISTS:
Power Purchase Agreement defines sale terms; CTU/STU are transmission operators; ISTS is the inter-state network. These govern evacuation approvals, metering, billing, and commercial viability.
PSS / Bay (AIS/GIS):
Pooling Substation and its switchgear “bay” (air- or gas-insulated) where plant power is stepped up and connected to the grid. It houses metering, protection, and interlocks—central to safe evacuation.
MC4 — PV DC Connector:
The standard, weatherproof plug for PV strings enabling quick, polarity-safe, low-resistance terminations. It speeds installation, improves serviceability, and reduces contact faults.
CT / PT — Current & Potential Transformers:
Sensors that scale current/voltage for protection relays and revenue meters. They enable accurate billing (SEM/ABT) and correct relay coordination.
SLD — Single-Line Diagram:
The one-page electrical map showing sources, switchgear, protections, and interconnections. It’s the common language for design reviews, operations, isolation/LOTO, and inspections.
ITP / QAP — Inspection & Test Plan / Quality Assurance Plan:
The who-what-how and acceptance criteria for checks across construction and commissioning. They reduce NCRs, standardise quality, and speed handovers.
FAT / SAT — Factory/Site Acceptance Tests:
Proof that equipment meets specs at the factory and after installation. They catch defects early, protect warranties, and build confidence before energisation.
Soiling / Degradation / PID / LID:
Dirt build-up and ageing losses; PID (potential-induced) and LID (light-induced) are specific mechanisms. Managing these via cleaning, monitoring, and remedies restores PR and protects warranties.
SEM / ABT Meter — Special Energy Meter:
Time-stamped metering for energy and deviations under ABT/DSM. It’s the basis for commercial settlement and grid discipline.
JSA / HIRA / PTW / LOTO / WAH — Safety Toolkit:
Job Safety Analysis, risk assessment, permits to work, lock-out/tag-out, and work-at-height. They make zero-harm execution possible and are mandatory in audits.
ALMM — Approved List of Models & Manufacturers:
MNRE’s authorised PV module list for designated schemes/tenders. It affects eligibility, bankability, and procurement choices.
STC / NOCT — Module Rating Conditions:
STC is lab nameplate; NOCT reflects typical field temperatures. They drive realistic yield estimates and inverter sizing expectations.
GHI / DNI / DHI / POA — Irradiance Types:
Global, direct, diffuse, and plane-of-array irradiance used in modelling and diagnostics. They inform site selection, shading analysis, and PVsyst/HelioScope simulations.
Specific Yield — kWh per kWp:
The normalised energy metric (kWh/kWp/yr) to compare sites and O&M performance. Higher specific yield signals better design, execution, and maintenance.