Day-Ahead Constraints

ISO-NE day-ahead transmission constraints with constraint, contingency, interface flag, and the publisher-signed marginal_value.

Congestion & Constraints data

Download data

Native record

constraint x contingency x day-ahead delivery interval

daily hourly market results publication cadence

Evidence

Cleared day-ahead market

A market outcome, not a physical observation

Time basis

Point-in-time records

UTC · event_time

Overview

The source values use the opposite sign from Ask the Grid's canonical shadow price, so analytical ranking should use atg.isone_constraints_da; a non-zero value is cleared day-ahead congestion evidence, not proof of a real-time binding condition.

Query contract

Select the latest ingested_at row per event_time, constraint_name, and contingency_name before ranking marginal values.

Analysis rules

Group only after preserving the declared grain: event_time, constraint_name, contingency_name.

Related analysis

sign-normalized day-ahead constraint ranking · Match event_time, constraint_name, and contingency_name to the canonical contingency field.

Interpretation

The source marginal_value is publisher-signed opposite to Ask the Grid's positive congestion-cost convention. Do not rank or report its magnitude as a positive shadow price; use the sign-normalized atg.isone_constraints_da dataset for agent analysis.
A day-ahead marginal value establishes cleared market congestion, not a real-time binding condition or the effect at a specific PNode.

Schema6

Column

Type

event_timeDateTime64(6, 'UTC')

constraint_nameLowCardinality(String)

contingency_nameLowCardinality(String)

interface_flagNullable(String)

marginal_valueNullable(Float64)

ingested_atDateTime64(6, 'UTC')

Sample data

event_time	constraint_name	contingency_name	interface_flag	marginal_value	ingested_at
2026-09-28 03:00:00.000000	Node_Shoreham_Export	Generic Constraint	N	-0.33	2026-09-28 03:30:15.327496
2026-09-28 03:00:00.000000	GRAHAM66BHEALN	205	N	-10.27	2026-09-28 03:30:15.327496
2026-09-28 02:00:00.000000	RUM-EX	Interface	Y	-3.91	2026-09-28 02:30:14.384398
2026-09-28 02:00:00.000000	GRAHAM66BHEALN	205	N	-14.1	2026-09-28 02:30:14.384398
2026-09-28 01:00:00.000000	RUM-EX	Interface	Y	-1.55	2026-09-28 01:30:15.165252
2026-09-28 01:00:00.000000	Node_Highgate_Export	Generic Constraint	N	-38.1	2026-09-28 01:30:15.165252
2026-09-28 01:00:00.000000	JOHNST_TT172S-3ALN	S171	N	-9.18	2026-09-28 01:30:15.165252
2026-09-28 01:00:00.000000	GRAHAM66BHEALN	205	N	-15.28	2026-09-28 01:30:15.165252
2026-09-28 00:00:00.000000	Node_Shoreham_Export	Generic Constraint	N	-0.96	2026-09-28 00:30:15.747254
2026-09-28 00:00:00.000000	Node_Highgate_Export	Generic Constraint	N	-0.54	2026-09-28 00:30:15.747254
2026-09-28 00:00:00.000000	JOHNST_TT172S-3ALN	S171	N	-12.97	2026-09-28 00:30:15.747254
2026-09-28 00:00:00.000000	GRAHAM66BHEALN	205	N	-3.32	2026-09-28 00:30:15.747254
2026-09-27 23:00:00.000000	Node_Shoreham_Export	Generic Constraint	N	-116.84	2026-09-27 23:30:15.478308
2026-09-27 23:00:00.000000	JOHNST_TT172S-3ALN	S171	N	-11.98	2026-09-27 23:30:15.478308
2026-09-27 23:00:00.000000	GRAHAM66BHEALN	205	N	-12.41	2026-09-27 23:30:15.478308
2026-09-27 22:00:00.000000	RUM-EX	Interface	Y	-13.01	2026-09-27 22:30:14.978876
2026-09-27 22:00:00.000000	Node_Shoreham_Export	Generic Constraint	N	-113.96	2026-09-27 22:30:14.978876
2026-09-27 22:00:00.000000	JOHNST_TT172S-3ALN	S171	N	-11.78	2026-09-27 22:30:14.978876
2026-09-27 22:00:00.000000	BASELINE52BHEALN	51BHE	N	-7.1	2026-09-27 22:30:14.978876
2026-09-27 21:00:00.000000	RUM-EX	Interface	Y	-11.74	2026-09-27 21:30:15.956034
2026-09-27 21:00:00.000000	Node_Shoreham_Export	Generic Constraint	N	-106.82	2026-09-27 21:30:15.956034
2026-09-27 21:00:00.000000	Node_Highgate_Export	Generic Constraint	N	-38.68	2026-09-27 21:30:15.956034
2026-09-27 21:00:00.000000	JOHNST_TT172S-3ALN	S171	N	-10.81	2026-09-27 21:30:15.956034
2026-09-27 21:00:00.000000	BASELINE52BHEALN	51BHE	N	-5.76	2026-09-27 21:30:15.956034
2026-09-27 20:00:00.000000	RUM-EX	Interface	Y	-12.31	2026-09-27 20:30:13.985304

Coverage

94.9% complete89 gap days1,643 days with data

Show coverage history

Coverage: 94.9%Days with data: 1,643Gaps: 89

2026

2025

2024

2023

2022

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Related congestion & constraints data

Related congestion & constraints data
Dataset	Description
ISO-NE Day-Ahead Binding ConstraintsISONE · hourly	Which transmission facilities bound in ISO-NE's day-ahead market and what each one cost, one row per interval and constraint. 24,146 rows, 2022-01 to now. Columns: event_time, constraint_name, shadow_price_usd_mwh, plus contingency. The shadow price is the marginal cost of the binding limit — what the market would have saved from one more megawatt of capability on that element. ISO-NE's negative source marginal values are sign-normalized here so larger positive values have the same meaning as the other markets. This is the table that answers WHY congestion appeared; a price spread between two locations shows that they separated but not which facility separated them.
LMP Avg Congestion DAISONE · ISO-NE source publication	ISO-NE's published LMP Avg Congestion DA source feed. This catalog page exposes the physical schema, coverage, and latest source rows without inventing a normalized grain for publisher-shaped snapshot fields. Use the documented key and event time when comparing revisions or vintages.
Single SRC Contingency LimitsISONE · ISO-NE source publication	ISO-NE's published Single SRC Contingency Limits source feed. This catalog page exposes the physical schema, coverage, and latest source rows without inventing a normalized grain for publisher-shaped snapshot fields. Use the documented key and event time when comparing revisions or vintages.
Total Transfer CapabilityISONE · ISO-NE source publication	ISO-NE's published Total Transfer Capability source feed. This catalog page exposes the physical schema, coverage, and latest source rows without inventing a normalized grain for publisher-shaped snapshot fields. Use the documented key and event time when comparing revisions or vintages.