+ Renewables Integration
International Symposium

into the Japanese Power
Grid by 2030
A Frequency Stability
and Load Flow Analysis!7th Dec. 2018

Power Systems with large amount ofRenewables (Distribution Generations)
Yoh YASUDA, Kyoto University

+Myth and Misunderstanding
about Renewables

2n “More outages would occur as More Renewables!”n Outages could occur even with no renewables.
n There are certain measures to avoid outages even with large

amount of renewables.
n “Distribution generations can prevent blackouts!”n Is is fact that grid stability could become worse as more DG.
n We should not be optimistic.
n However, many measures have been proposed worldwide.

n Need for quantitative grid analysis

+ Challenging by large amount ofDistribution Generations

3n “Inertia Problem”
would be more severe
OVERARCHING
GOAL

in higher share of distribution generations
most sever situation in middle stage(source) MIGRATE – Massive Integration of Power Electronic Devices, Stakeholder workshop, Brussels, 6 April 2017

+ Fundamental Equation of Turbine
GeneratorAngle
Inertia MomentdωJ=Tdt

4Frequency
TorqueSimilar asEquationof MotionmTmMachine
TurbineTorquedv=Fdt

Te

Generationdω
J= Tm − TedtElectricity
Torque+Synchronous and Asynchronous
Generators

5Sync. Gen.

Async. Gen.
(source) Mark O’Malley: Wind Integration in Ireland: a National Effort with International Consequences,
JWEA Wind Integration Workshop (2012)+

Vertual Inertia (GE Energy)

6(souce) N. Miller: “Impact of frequency responsive wind plant controls of grid performance, GE Energy (2010)

Vertual Inertia (Risø-DTU)
20% Wind Power Penetration

1.005

Basic Case
Without IR
With IR

10.995Frequency [pu]+Figure 6 illustrates the frequency excursion during the IR event defined in Table 1 bothfor the basic case (i.e. no wind power) and the case with 20% wind power online
7penetration with and without activation of IR ancillary service inside WPPs. Since theconventional power plants are not replaced in 20% wind power scenario, there is notconsiderable difference between the basic case (0% wind power) and 20% wind power
scenario without IR contribution.

0.99

0.985
Safety margin0.98
Load shedding limit

0.975

0.97

0510152025Time [s]3035404550Figure 6: System frequency excursion
duringIR event,speed
and 20%(souce)
A. Hansen
and0.86pu
M. Altin:wind
Impactof advanced
wind power
wind power penetration ancillarywith andservices
without on
inertial
fromWind
WPPs.
powerresponse
system, DTU
Energy Report 2015

meeting the non-techno-economic goals of a country’s
energy policy. By building assessments on meaningful
stakeholder consultation, decision makers also canensure that a consensus is established around thelegitimacy of results (NASEO, 2014; OLADE, n.d.; Wilsonand Biewald, 2013).

+or level of detail, of analysis within the timeframe. The
discussion below focuses on planning aspects in relation
to the time horizon; the issues of timeframe and time
8resolution are discussed fully in Appendix 2, in relation
to modelling tools for each planning step.

Power System Analysis

Very active worldwide.
How about in Japan?

Figure 3: Transition planning components and time horizon

Typical time resolution

Typical timeframe

Generation expansion planning
Seasonally to sub-daily

20-40 years
Geo spatial planning

Seasonally to sub-daily(static)

5-20 yearsDispatch simulation
Weeks-years

Hourly to sub-daily

Sub-hourly tosub-seconds

Technical network studies

Near-term

Today’s
discussion

Planning time horizon

SnapshotLong-term(source) IRENA: Planning for the Renewable Future (2017)+Power System Analysis

Today’s
discussion

9(source) IRENA: Planning for the Renewable Future (2017)