100kWp System in Australia

100kWp Inverters Compared: SolarEdge vs. Schneider
Modules Used: Canadian Solar CS6U-340M CPTL
System Overview:100kWp

Introduction

In 2006, SolarEdge invented an intelligent inverter solution that has changed the way power is harvested
and managed in PV systems. Since beginning shipments in 2010, SolarEdge has shipped more than 4.7
GW of its DC optimized inverter solution and its products have been installed in PV systems in more
than 100 countries, making it a top 3 global inverter manufacturer.

SolarEdge Commercial Solution

  • More energy – module-level optimization
  • Longer strings – reduced BoS cost
  •  Enhanced O&M – module-level monitoring
  •  Superior safety solution

A Higher Lifetime Value

The SolarEdge optimized DC inverter solution enables higher system lifetime value by increasing revenue and reducing installation and maintenance costs. Power generation is optimized at the panel level, which minimizes power losses and leads to a higher lifetime revenue from the PV systems. While the initial cost of the SolarEdge solution is generally slightly higher than the equivalent traditional inverter system, the total installation cost, such as BoS components, as well as the lifetime operations and maintenance cost, is lower. This makes the SolarEdge solution a more economically attractive throughout the system lifetime*.

System Design Alternatives

Modules: 294 x Canadian Solar CS6U-340M CPTL = 99.6 kW DC
Two inverter alternatives were considered for this project

  • Schneider:
    • 4 x CL25000 inverters
  • SolarEdge:
    • 4 x SE25k inverters
    • 147 x P700 power optimizers

This document shows the installation and lifetime maintenance cost savings when using SolarEdge
compared to a traditional system.
Additionally, a PVsyst analysis shows the added energy for SolarEdge vs. a traditional system on

BoS Cost Saving

Introduction – Longer Strings

The SolarEdge system works at a fixed string voltage, which allows connection of much longer strings compared to traditional inverters.

Typical String Layout Comparison

The diagram below shows an example of a module block with a string design for SolarEdge Vs. a typical string inverter. SolarEdge fixed string voltage allows for longer string, reducing the amount of DC cabling. In this example, SolarEdge manages to 70% less string cabling than the string inverters

Single Line Diagram

Typical Inverter Schematic

All final designs are at the discretion of and responsibility of the site project engineer

Note – In a SolarEdge system, the string current is limited to the optimizer’s maximum output current, even if module current increases due to ambient conditions. Therefore no safety margin is needed when calculating maximum string current.

SolarEdge String Layout Example

Sample 30 modules string

BoS Comparison

  • Longer strings lead to reduction in cabling cost as well as ease of design and installation
  • In this project, it is estimated that SolarEdge will save 49% of the BoS cost compared to Schneider*
  • The plans below show strings layouts for SolarEdge and Schneider. The green lines represent additional DC cabling required for the home runs

Notes – SolarEdge configuration has 10 strings only comparing to 16 strings with competitor. Which resulting to less DC cabling, less DC cabling losses, less incidence of Insulation faults which may avoid late start of inverter (at morning hours)

– Competitor inverter require additional cost for Datalogger, it’s Warranty Extension cost and Monitoring portal extra fee (if exist)

Enhanced Asset Management

SolarEdge power optimizers constantly monitor the performance of the modules to which they are
connected, providing full visibility into system performance and enabling real-time fault detection and
remote troubleshooting.

Module issues such as underperformance, can be either detected 

remotely on the monitoring platform, or notified by automatic alerts, and their location will be pinpointed on a virtual site map, thus reducing
the number of site visits, and the time spent on site.

Superior Safety Features

PV systems are safe and do not inherently pose danger to people or property. However, with a traditional inverter, as long as the sun is up, PV wires are energized with high DC voltages.

With SolarEdge, whenever AC power is turned off, DC wires are designed to de-energize providing automatic protection to installers, maintenance personnel, firefighters and property. The SafeDC™ feature meets the highest German and European safety standards (VDE 2100, IEC 60947).

SolarEdge inverters comply with the UL1699B arc detection standard designed to mitigate the effects of some arc faults that may pose a risk of fire

Added Energy

Introduction

Modules connected in a string have different Maximum Power Points (MPPs) leading to unavoidable mismatch. There are different sources for module mismatch such as manufacturing tolerance, soiling (dust, snow, leaves), temperature differences and partial shading. Module mismatch lowers the energy yield of the entire string. In addition to the inherent mismatch, each PV module degrades at different pace, increasing the power mismatch and the related loss of energy over the years. The SolarEdge power optimizers eliminate mismatch-related power losses by performing maximum power point tracking (MPPT) at the module level. With SolarEdge, each module generates at its maximum power at all times, and underperforming modules do not affect the production of the entire string.

Standard String Inverter

Reduced O&M Cost

Alerts for modules & inverters underperformance Know before you go –

  • Identify underperformance
  • Use charts to analyze underperformance
  • Schedule maintenance according to problem severity and effect on system performance
  • Fewer trips to site, less time spent on-site

Remote diagnostic & analysis

Using SolarEdge monitoring portal, PID problems can be detected in “two clicks”. Looking at the string modules power, degradation of power in the last modules is shown (closest to the negative pole)

No need to send technicians to the roof – modules voltage is measured remotely.

Bypass diode seems to have short circuited – faulty module shows 2/3 of the voltage. Installer can proactively provide service at his convenience

PVsyst Analysis

PVsyst was employed in this project to simulate the first and 20th year energy production of the PV system using string inverters, compared to the same design using SolarEdge inverters and power optimizers. The simulations show a growing SolarEdge advantage due to uneven module aging which increases mismatch between modules with time. The results are summarized in the table below, followed by PVsyst losses diagrams in the following page*.

PVsyst Reports – Loss Diagrams

The following Sankey diagrams show detailed system losses for both SolarEdge and Schneider. While most modules age to an acceptable degree of up to 80% of their nameplate output over 20 years, the different rate at which they age introduces aging mismatch. The mismatch between modules will increase over time as modules age at a different rate. Module-level optimization by SolarEdge power optimizers eliminates losses due to the increasing aging mismatch. To this end both systems were simulated for the power output on year 1 and year 20 of operation.