AN IS8000APP04-01EN
1. Introduction
A power conditioning system (also referred to as an
inverter, PCS, or power conditioner) is used to convert
the DC power generated by solar modules or windmills
into AC power in systems that produce renewable
energy that has been introduced as a response to global
environmental issues, such as a wind power generation
system or solar power generation system including a
mega-solar power system. This conversion efficiency is
improving every year. One of the goals of the power
conditioner developers is to develop ones with low
conversion loss, which are highly competitive in the
market.
The efficiency measurement method for power
conditioning systems for photovoltaic power generation
is specified in JIS C 8961 in Japan and the international
standard IEC 61683. Regulations concerning efficiency
measurement may differ for each country and some
countries specify the methods of measuring not only the
maximum efficiency but also Euro efficiency or CEC
efficiency.
While maximum efficiency is the efficiency data under
specific conditions where efficiency is maximized,
Euro/CEC efficiency is the efficiency that is obtained by
measuring the efficiencies at multiple points under light
load to rated load and weighting them according to the
load factor.
There are various problems in interconnection to the
grid. If a large amount of output from solar power
generation, wind power generation, or others are
connected to the power grid and power conditioners get
disconnected all at once due to the disturbance of the
grid, the power quality is greatly affected. To prevent
such a problem caused by simultaneous disconnection
or the like, a power conditioner needs to have continuous
operation performance that is the ability to continue its
operation (stay connected to the grid) even when an
Application Note
Evaluation Test of Power Conditioning System for
Solar/Wind Power Generation
instantaneous voltage drop occurs. The requirements for
the continuous operation performance of dispersed
generators, which is necessary to ensure the power
quality even during grid disturbance, are continuously
developed.
Evaluation of maximum efficiency, Euro efficiency, and
CEC efficiency includes a voltage fluctuation test,
frequency fluctuation test, and temperature rise test.
Power measurement using a power meter, checking of
instantaneous waveform fluctuations using an
oscilloscope, or high-speed data acquisition equipment,
and temperature measurement tests are conducted
around the world.
2. Challenges
As the amount of renewable energy generated often
varies depending on natural conditions, the power grid
may become unstable due to a sudden increase in
power generation. The power grid also becomes
unstable when lightning strikes the grid and the power
generation system side is disconnected all at once or
when an event occurs where the generated power
fluctuates due to weather changes and the voltage and
frequency of the power grid fluctuate. Developers of the
power conditioning system may want to examine such
events by continuously measuring the fluctuations in
active power, reactive power, voltage, frequency, power
factor, and efficiency during the events. The main
purpose of a waveform measurement instrument is to
continuously monitor a grid for a long time and capture
abnormal data, but on the other hand, the developers
also want to capture transient events and changes with
high-speed sampling at the same time. It is difficult to
perform the long-term measurement and capturing of
fast abnormal events simultaneously. It is even more
difficult to capture the numerical changes in power data
efficiently and analyze the data at the same time with the
long-term measurement and high-speed capturing.
3. IS8000 Solution
â– Data checking and operation by online monitor
â– Integration of DL software and WT software
â– IEEE1588 WT/DL time-synchronized display
â– Integrated file management by project file
â– Utilization of reliable power data with guaranteed
accuracy
â– Automatic report creation using waveform and
power meter data
IS8000 Integrated Software Platform
YOKOGAWA TEST & MEASUREMENT CORPORATION tmi.yokogawa.com
IS8000 Application Note
4. IS8010 Solution (Detailed descriptions)
4.1 Data checking and operation by online monitor
The online monitor operation allows measurement
instruments to be controlled remotely from a PC via a
communication interface.
The touch panel screen (control screen) of the DL950
ScopeCorder or WT5000 Power Analyzer main unit is
displayed on the PC screen. A user can freely change
the settings or check the measured waveform and power
meter data from a PC at a remote location in the same
manner as operating the measurement instrument.
There is no need to newly learn the operations of
software that are different from those of the instrument
main unit. The user can simply check the settings and
waveform display to make sure there is no problem, then
begin collecting the waveform or power meter data.
The waveform on the DL950 located away from the
control room can be checked on the PC, which enables
efficient data collection without the trouble of going back
and forth between the test room and control room to
save the waveform data or change the setting conditions.
Figure 1. DL950 remote control screen
Figure 2. WT5000 remote control screen
4.2 Integration of DL software and WT software
Conventionally, the oscilloscope software and power
meter software have different file formats and it is
necessary to collect data using different software tools.
The newly developed integrated measurement platform
IS8000 can be used as one integrated measurement
software to meet the measurement needs for
synchronous measurement of waveform data and power
meter data. By integrating the data collection software
tools, it has become possible to significantly reduce the
work of organizing and managing files, compared to the
way of collecting data by separately performing
measurements with an oscilloscope and a power meter
and saving the measured data.
Figure 3. Startup screen of IS8000 integrated measurement platform
Figure 4. Integrating a project file and divided files