Permanent project revision
Revision 2026-08-20-claim-baseline · effective 2026-07-26
Superseded. A later revision exists: 2026-08-21-source-dates →
Created the first structured Evidence Passport with 5 claims and 8 source dossiers.
sha256:2eb6872779ce636061906b024c6380206447c575dde6afc784697d508cc0eb31
add /evidencePassport — Added claim-level evidence mapping and source dossiers.add /revisionHistory — Established a permanent, hash-addressed baseline revision.The text below is copied verbatim from the published record. Each claim names the source dossiers that carry it; caveats stay attached to the claim they qualify.
clm-d401d828acc6409d
quantitative
Since 1981 Mumbai's grid has been able to cut itself loose: automatic under-frequency and rate-of-change-of-frequency relays disconnect the city from Maharashtra's transmission network during an outside disturbance, leaving the generation inside the city to carry the load
clm-c9dc69fbbe485728
quantitative
It failed publicly on 12 October 2020. After transmission lines tripped near Kalwa the island did separate, but collapsed within minutes with roughly 1,394 MW of local generation against more than 2,800 MW of demand, and parts of the city stayed dark for 2 to 15 hours
clm-25050ab26a79df23
descriptive
India's power minister attributed the outage to human error, Maharashtra's energy minister backed a cyberattack theory, and the firm that had reported Chinese-linked intrusions into India's power sector called the link to the blackout unsubstantiated
clm-868d419761a6c1ad
quantitative
Tata Power asked IIT Bombay to rework the scheme, and a revised multi-level version was conceptually agreed among the utilities and grid operators in January 2024
clm-b082d3c668fffefe
quantitative
27 of 37 major grid disturbances since 1981 were ridden out on the Mumbai island (utility figures reported in 2012; not independently audited)
This layer records what is known about each source, what is still missing, and the exact snapshot this page is rendering. A missing date, archive or hash stays visible as missing.
Awaiting operator and domain-expert review; publication of this revision implies neither.
sha256:2eb6872779ce636061906b024c6380206447c575dde6afc784697d508cc0eb31
src-8ecd66a889868e35Authority document for the scheme as it stands (file dated January 2025): multi-level islanding covering the Tata Power and Adani Electricity systems, under-frequency load shedding and relay settings, Mumbai peak demand around 4,000 MW against about 1,877 MW installed inside the city, and the revised scheme conceptually agreed at a meeting on 17 January 2024.
src-b92ef17261de3407Independent technical account (2007): the separation runs on reverse-power and under-frequency relays, not centralised control; describes a February 2005 separation as the 14th successful islanding since 1997.
src-49d914ab784d8899Scheme designed by Tata Power in 1981 and later upgraded with the other city utilities; carries the utility record of 37 major grid disturbances since 1981 with 27 survived.
src-a58ef384d5d8d698Trade-press reconstruction of 12 October 2020: a 400 kV line tripped at 09:58 on a phase fault, two more followed at 10:05; the island separated but could not hold a sudden 1,000 MW drop, with about 1,394 MW available against more than 2,800 MW of demand; outage lasted 2 to 15 hours.
src-c71e5e8c9fe5e34ePeer-reviewed analysis (2022) of the cascade and of why the unintended island did not survive, citing a high rate of change of frequency. Publisher blocked automated fetch; existence and subject confirmed via indexing services.
src-0572af0207776db7Tata Power says the scheme needs to be relooked because embedded generation of 1,877 MW is now less than half of peak demand, and engages IIT Bombay to study modifications.
src-db82b733c4427c4aFact-check separating the claims: the security firm's February 2021 report on a China-linked group, which itself called the link between the outage and the malware unsubstantiated; the state energy minister endorsing the cyberattack reading; the union power minister stating two investigating teams found human error.
src-e017fe578f24208dOn a later outage in February 2022: a 220 kV line tripped, two units tripped and about 850 MW of Mumbai load was lost. Shows the 2020 event was not a one-off.