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Tokyo Metropolitan Microgrid For High Reliability

Current status, energy mix, organizations, suppliers, equipment, controls, reported specifications, and project updates—with source-level citations.

CoverageDetailed public record
Named organizations2
System facts12
Sources reviewed4
Evidence reviewed2026-07-20

The legacy title refers to Tokyo Electric Power Company's high-voltage Tokyo Metropolitan Power System islanding-protection scheme, not a neighborhood DER microgrid or Tokyo Metropolitan University laboratory. Installed around 2001, it protects politically/economically critical central-city loads by intentionally separating a selected area and rapidly balancing generation, load and reactive power after loss of the 275 kV ties to TEPCO's 500 kV bulk grid. No solar, wind or battery belongs to the documented scheme.

Research status
A 2001 IEE conference paper documents installed protection and actual operating experience, and a 2013 Japanese microgrid overview still presented the system as Tokyo's reliability example. No recent TEPCO source identifies its current relay/controller generation, protected boundary or retirement, so historical operation is verified but 2026 status is unresolved. The legacy page's 'NA storage' should not be converted into a zero-kWh battery claim; storage simply was not part of the source record.
Historical classification
Urban
Reported capacity
See component specifications
Coordinates
35.68949, 139.69171
Evidence note: “Every company” cannot be proven from public material alone. This page lists every organization found in the recovered record and reviewed sources, preserves unknown roles, and explicitly marks undisclosed controller or equipment details.
Report missing evidenceResearch methodology

Project delivery

Who was involved in Tokyo Metropolitan Microgrid For High Reliability?

2 publicly identified organizations. Where a recovered source named a participant without explaining its work, the role remains explicitly unspecified.

Organization

S. Agematsu, S. Imai, R. Tsukui and H. Watanabe

TEPCO-affiliated authors documenting design and actual operating experience. [2]

Organization

Tokyo Electric Power Company (TEPCO)

Owner/operator and developer of the metropolitan transmission/subtransmission islanding protection scheme. [2][3]

System evidence

Energy mix, capacity, and specifications

Values can describe different project phases, generation sources, storage systems, or other components. Source citations are attached to each figure so discrepancies remain visible.

Storage
NA [1]
System scale
Historical overview diagram labels a 1,515 MW metropolitan subsystem, approximately 410 MW of local generation and a 78 MW most-important load area. These are transmission-system operating quantities, not installed microgrid DER nameplates. [3]
Network voltages
Fed from the 500 kV mesh through parallel 275 kV overhead lines and three colocated 275 kV underground cable circuits; the protected metropolitan network uses 275, 154 and 66 kV underground cables. [2]
Generation and energy mix
Historical diagrams show large local thermal generating units plus bulk-grid imports. The cited sources provide no plant names/fuels, annual mix, renewable assets or storage. [2][3]
Protected load
The control sheds/islands down to the most important area when the separated metropolitan subsystem cannot balance its full load; exact current customers and facilities are intentionally/not publicly identified. [2][3]

Controls and hardware

Equipment and controller details

Manufacturer and model are shown only when a source names them. Generic descriptions are not converted into guessed product assignments.

01

Islanding protection system

Model not publicly disclosed

TEPCO protection/automation performing separation detection, active-power balance through staged load shedding and reactive-power/voltage balance. Commercial relay/controller models were not disclosed. [2]

02

Transmission switching

Model not publicly disclosed

High-voltage breakers and underground-cable network form the intentional island; exact substations and breaker models are not public in the sources. [2]

03

Energy storage/DER

Model not publicly disclosed

No battery, PV or wind equipment is documented; do not merge the unrelated Miyako NAS-battery demonstration shown elsewhere in the 2013 presentation. [3]

Technical record

Architecture, performance, and project updates

Concise technical facts, milestones, operating results, and later developments. Dated notes distinguish historical design claims from current evidence.

  • Failure scenario

    A common-route failure of the 275 kV ties can leave the metropolitan subsystem severely generation-deficient and capacitive. The scheme separates it, sheds load to active-power balance and controls reactive balance to preserve the priority island. [2]

  • Why radial

    Metropolitan sub-power systems could not simply be interconnected because short-circuit fault-current limits constrained network topology. [2]

  • Classification warning

    This is controlled islanding of a transmission/subtransmission area—microgrid-like in emergency behavior but far larger and architecturally different from a campus/community microgrid. [2][3]

  • Current-data gap

    No authoritative public update through 2026 confirms modernization, retirement or operational events; present tense should be avoided beyond the historical sources. [2]

Provenance

4 sources

Primary owner, government, university, supplier, and engineering sources are preferred. Archived references preserve claims whose original pages moved or disappeared.

  1. [1]
    Recovered Microgrid Projects record

    Internet Archive · Archived source · captured 2020-07-06

  2. [2]
  3. [3]
    Status of Microgrids in Japan — Korea Smart Grid Week 2013

    Reiichiro Fujimori presentation (third-party document host) · Secondary research

  4. [4]
    Recovered Tokyo Metropolitan Microgrid record

    Microgrid Projects · Archived source

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