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PV Power Plant Inspection Service | NPC incorporated

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PV Power Plant Inspection Service

PV Power Plant Inspection Service

Our inspection performed so far

 Click here to see Case Study 

Inspected capacity (as of June 30, 2020)

2,170MW detail

< 2MW

122 sites

2MW-10MW

29 sites

10MW-50MW

37 sites

50MW-100MW

6 sites

> 100MW

4 sites

350MW

*Some power plants have been inspected several times.

Service Outline

Provides inspection services on site at the same level as PV panel manufacturers

We provide various performance/safety tests including insulation resistance measurement, ground resistance measurement as well as string I-V inspection, EL inspection, and IR inspection using thermography.

We provide services of pre-operation voluntary test and pre-operation self check, mandated by revision of FIT scheme in 2017 for PV plants of 500kW – 2,000kW.

Through partnership with cooperating companies, we also cover integrated O&M services including regular safety checks performed every month or year.

Total services covering DC to AC

Covered by NPC

Covered by NPC

Completion test

Pre-operation voluntary inspection

Pre-opereation self check

Performance/Safety

I-V characteristic inspection

Voc measurement
Grounding resistance measurement
Disconnection check

Visual check

Insulation resistance check

Ground fault resistance test

EL inspection

IR inspection

Safety

Monthly check

Regular check

Annual check

Introducing our integrated inspections/maintenance service of PV power plants
(5 min. 51 sec. with sound)

Advantages of NPC

  • Providing our unique analysis ability and detailed reports
  • Superb on-site flexibility based on a number of inspection performances
  • Good cost performance through nationwide network
  • Proposing a wide variety of inspections covering DC to AC

Main inspections

I-V inspection

Use of “Rakit,” our multi-functional high-speed I-V measurement system, shortens inspection time and saves power loss to the minimum level.

Highly accurate analysis results will be automatically provided through the data conversion under STC (temperature: 25℃, irradiance: 1,000W/m²).

I-V inspection

I-V inspection

On-site EL/PL inspection

Use of “EPTiF,” our original EL/PL inspection machine enables us to perform EL/PL inspections during daytime without removing panels. It provides detailed inspection in an easy and safe manner, identifying all the defects and their causes from micro-cracks to disconnection and PID.

On-site EL/PL inspection

On-site EL/PL inspection

IR inspection (by thermography)

Temperature measurement by IR using the high-resolution thermographic camera (E75) by FLIR identifies faulty panels with hot spots, etc. Efficient IR inspection using a drone is also available.

IR inspection (by thermography)

drone IR

Other inspections

Using “DCFT,” DC safety inspection device for PV panels, we check ground fault resistance, break in electric path, bypass diode disconnection, etc. and identifies faulty panels in a short time. We also provide visual check required at pre-operation voluntary inspection, insulation resistance measurement, ground resistance measurement, dielectric strength test. Efficient barcode reading is also available, utilizing our experience.

Other inspections

Other inspections

NPC Original Maintenance Service

According to our customer's needs, we provide various inspection/maintenance services.

Case study

Spot inspection

■Capacity : approx. 4MW / 3 years after installation
■Inspection: I-V inspection, EL inspection, report
■Result: significant power decline found in approx. 70 strings I-V data. As a result of EL inspection afterwards, PID occurrence was detected and dozens of panels were exchanged.

Spot inspection

Spot inspection

Completion inspection (Pre-operation voluntary inspection)

■Capacity:approx. 20MW
■Inspection: I-V inspection, Voc/polarity check, report
■Result: disconnection of interconnectors/connectors and faulty soldering were found in  approx. 70 strings I-V data and dozens of panels were exchanged.

Completion inspection (Pre-operation voluntary inspection)

 

Completion inspection (Pre-operation voluntary inspection)

■Capacity:over 50MW
■Inspection: Insulation resistance measurement, ground resistance measurement, dielectric strength test,  I-V inspection, bar code reading, report

 

 

Regular maintenance

■Capacity: 100kW rooftop system
■Inspections: 3-month regular check (visual check, insulation resistance measurement,  Insulation resistance measurement, ground resistance measurement, report)
Annual check  (regular check, safety check using “DCFT,” report)

 

 

Maintenance Service Flow

  • Inquiry
  • Obtaining power plant information
    (spec of panels and junction boxes, connection block diagram, panel distribution drawing, etc.)
  • Proposal of estimates
  • On-site inspection
  • Providing analysis report

Case Study

Matsuyama Foundation for Culture and Sports Promotion

Outline of the PV system

 

  • Start of operation: 2001
  • Location: Matsuyama Outdoor Activity Center, Matsuyama city, Ehime Prefecture
  • Number of panels: more than 400 panels deployed on the ground and rooftop, respectively
  • Generation capacity: 100kW

 

Purpose of inspection

We inspected the system to confirm if it was operating in a sound condition after more than 15 years of operation, both in the view of safety and performance.  If any problems were found, we were to identify the causes.


Contents of inspection

 

We performed visual inspection, Voc measurement, disconnection test, ground fault resistance test, I-V inspection, and IR inspection using thermography camera in one day.


Result of inspections

 

We found panels damaged by heat, panels with disconnection and broken glass, panels with excess heat, and insufficiently-insulated strings.  We issued a report stating each problem and the considered causes, and secured safety by disconnecting the strings with insulation problem.  We also exchanged the panels with disconnection to proper panels.

 

matsu1  matsu2 
 matsu3 matsu4 

The panels installed on the rooftop were estimated to have caused high resistance and open bypass circuit, considering the significantly lower FF compared with those on the ground.  As they were installed on the rooftop, where dissipation of excess heat was limited, we recommended the customer to remove the panels to avoid a fire risk.  As a result, the whole rooftop system was moved away.  As to the ground-mounted system, all the defective panels were exchanged to good-quality panels and secured safety.  Since then, the system has continued to generate power without any problem.  The customer asked us to perform regular inspections and maintains the soundness and safety of the system.  

 

Customer's voice - reviewing our inspections

"When we found abnormal operation of the rooftop PV system, we asked NPC for inspections of our PV systems.  As a reult, several defects including damage by heat were found.  To secure safety, we removed all the panels installed on the rooftop. 

Since NPC provided us with appropriate proposals from a series of inspections to the actions in the future, we were able to solve the problem quickly.  We thrive to operate the Outdoor Center safely and comfortably by performing safety check of the ground-mounted panels at the regular inspections."

Examples of PV Power Plants Inspected So Far

Company J

Company J

Site: Yamaguchi Pref.
Capacity: Approx. 2MW

Company J

Company J

Site: Yamaguchi Pref.
Capacity: Approx. 9MW

Kikuno Co., Ltd.

Kikuno Co., Ltd.

Site: Ehime Pref.
Capacity: 844.48kW

Company J

Company J

Site: Yamaguchi Pref.
Capacity: Approx. 15MW

Chudenko

Chudenko

Site: Hiroshima Pref.
Capacity: 15kW

Kishiro Co., Ltd.

Kishiro Co., Ltd.

Site: Ehime Pref.
Capacity: 2.19MW

Lixil

Lixil

Site: Kumamoto Pref.
Capacity: 3.75MW

Matsuyama Kanko Golf

Matsuyama Kanko Golf

Site: Ehime Pref.
Capacity: 1.43MW

Company A

Company A

Site: Shiga Pref.
Capacity: approx. 1MW

Mirait Technologies

Mirait Technologies

Site: Chiba Pref.
Capacity: 32MW

JFE Technos

JFE Technos

Site: Tochigi Pref.
Capacity: 13MW

JXTG Energy

JXTG Energy

Site: Kagawa Pref.
Capacity: 1.4MW

JXTG Energy

JXTG Energy

Site: Ehime Pref.
Capacity: 1.1MW

JXTG Energy

JXTG Energy

Site: Ehime Pref.
Capacity: 1.4MW

JXTG Energy

JXTG Energy

Site: Ibaraki Pref.
Capacity: 2.0MW

JXTG Energy

JXTG Energy

Site: Akita Pref.
Capacity: 2.4MW

   

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