Japanese Grid Code · 2018-12-12 · Osami Tsukamoto Professor Emeritus, Yokohama National University Yokohama, Japan Satoshi Morozumi Smart Community Dept., New Energy and Industrial
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Osami Tsukamoto Professor Emeritus, Yokohama National University
Yokohama, Japan
Satoshi Morozumi Smart Community Dept., New Energy and Industrial Technology
Development Organization Kawasaki, Japan
Contents -Background -Introduction -Anti-Islanding -FRT -Certification, Collaborative work -Concluding remarks
IRED2014 Kyoto
Annual growth Growth rate
32%
Growth rate 9 %. Growth rate
5 %.
FiT
PV
Wind p. Hydro p. Geothermal Biomass
Growth of installation capacity of renewable energy in Japan
Back ground
Due to recent rapid growth of introduction of distributed energy systems, amount of works to permit their introduction to grid increases rapidly.
Well regulated grid code is necessary to establish for safe operation of
power grid keeping power quality.
Aug. 1986 Establishing “Grid connection Technical Requirement Guideline
Oct. 2004 Update to “Grid connection Technical Requirement related to Power quality Guideline”
Government The Agency for Natural Resource and Energy
2006 Establishing “Grid-interconnection Code” JEAC 9701-2006
2001 Establishing “Technical guidance of interconnection for distributed power supply ” JEAC9701
Domestic Standard The Japan Electric Association (JEA: Non governmental )
Each utility prepares its own “ Grid Code” (according to the codes)
Utilities
Updating Year by Year
Introduction
The Newest is “JEAC 9701-2012” “JESC E0019(2012) ” ( Revised every year based on requirements from utilities including general ones and amendments are published timely.)
Authorized by those two committees in the Japan Electric Associates “Specialized sectional committee regarding Grid
Interconnection “ (Chairman : Prof. Osami Tsukamoto) “Japan electric standard and code committee” (Chair : Prof.
Kunihiko Hidaka)
Low voltage distribution line (100/200V):
・Single or three phase power sources can be connected.
・Principally, only inverter based power sources can be
connected.
・Anti-islanding is required.
High voltage distribution line (6.6kV-33kV):
・Principally, three phase rotating machine or inverter
based generators can be connected.
・Anti-islanding is required.
Spot Network:*
・Principally, reverse power flow is not allowed.
Extra High Voltage (Sub transmission) :
・Anti-islanding is not required, if frequency relay is
installed, or if transfer-interrupting is available.
* 22kV or 33kV, Three phase parallel underground cable system, where customer connected to
secondary side of transformer.
When a fault happens on the grid, anti-islanding is required,
To protect operators who recover system from shock
hazard,
To protect inverter from over current accident., To protect home appliance from damages due to over voltage.
Grid code JEAC9701-2006 requires that islanding must be detected within 0.5 sec in the case of using a passive method and within 0.5sec.-1.0 sec in the case of using an active method.
6
Anti-Islanding
7
Newly developed anti-islanding system can detect islanding within 0.1 sec. and cope with a fault by a short between
primary and secondary of a pole transformer.
Substation Circuit Breaker Open in 0.9 sec by detection of fault current by OCR
Pole transformer
Anti-islanding system must function within 0.1 sec.
Fault caused by a short between primary and secondary winding of a pole transformer 600V over voltage apearsens across grounding resistance
CB in substation will be opened in 0.9 sec after a fault happens. Then, PV must stop generation within 0.1 sec to protect home appliances. JIS requires home appliances to with stand 600V for1 sec..
Demonstration of clustered PV (Ota-Project) (2002-2007) Development of new anti-islanding method.
30 inverter test-bed for testing anti-islanding method.
Technology development for testing anti-islanding(2008-2009)
Standardization of testing method of anti-islanding for cluster PV.
Discussion about FRT requirement for PV
Reflected to Grid Interconnection Code
Follow Up project of clustered PV(2008-2009) Replacement of PCS including new anti-islanding system
Research about International Standard of PCS for distributed generators (2010-2011)
Disclosure of the patent of new anti-Is. method to the domestic manufactures
Research about international standardization of PSC
US-Japan Smart Grid Demonstration in New Mexico(2009-2015)
Comparison of testing of anti-islanding methods
Mention of anti-islanding technique to a standard of IEEE
8
9
Large residential area where more than 800 houses are constructed. PVs were installed on roof tops of 553 houses Demonstration test of power quality and safety
PV systems:
Number of PV
systems installed: 553
Total PV capacity:
2,129 kW
Average PV capacity:
3.85 kW
Battery storage:
Number of
installations: 550
Storage capacity:
4704 Ah≒9 kWh
11
Detection by “the Frequency feed back” method
Injection of 2Hz reactive power
Injection of maximum reactive power
Detection of frequency drop
2Hz reactive power is fluctuated synchronously with GPS signal or wave clock signal. (There was an objection from the utility side because the system was dependent on other party’s facility.)
Reactive P
ow
er
frequency
12
By detection of change of commercial frequency voltage or harmonic voltage system starts injection of reactive power
Detection by “the Frequency feed back” method
Injected Reactive Power
commercial frequency voltage
Frequency Change
Injected Reactive Power
Harmonic frequency voltage Frequency Change
Islanding starts
Step injection of reactive power
In the case of commercial frequency voltage is changed
In the case of harmonic voltage is changed
2012 - 2016
2016 -
Voltage
Voltage
Keeping operation
Gate Block or keep operation
Keeping operation
Gate Block or keep operation
PCS Output
PCS Output
80% recovery within 0.5 sec when voltage drop is above 30%. And 1.0 sec for below 30%.
80% recovery within 0.1 sec when voltage is dropped above 20%. And 1.0 sec for below 20%.
FRT for PV and wind power for all voltage
levels
Change as Step
50Hz Area: +0.8Hz 3cycles
60Hz Area: +1.0Hz 3cycles
Lumping Change
50Hz Area: +2Hz/sec up to 51.5Hz
50Hz Area: -2Hz/sec down to 47.5Hz
60Hz Area: +2Hz/sec up to 61.8Hz
60Hz Area: -2Hz/sec down to 57.0Hz
FRT
The system has to continue operation for
Step change Lamp change
sec Sec Sec
Continue operation
Continue operation
15
Testbed in Sandia National Lab. In New Mexico (up to 8 PCS)
Testbed in Akagi site in Japan. (Up to 30 PCS)
Testing PCS each other
Technical exchange of anti-islanding and FRT system for PV
Japanese anti-islanding system is being involved as “Recommended Practice” in IEEE 1547.8.
This testbed was established for testing and certificating new PCS standard in 2012 based on JEAC9701-2012.
The grid code is continued to be revised year by year based on requests from utilities ( general ones and others) and updated according to progresses of interconnection technology.
Questionnaires are distributed to utilities to collect requirements by JEA (Japan Electric Association).
Continuous efforts are exerted to improve the grid code for smooth introduction of distributed power supplies to utility grids.
Thank you for your attention.
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