SCED Violated Constraints

This section describes interfaces used to retrieve binding constraint in SCED. SCED Violated Constraints are only provided for RTM market. The request message would use the following message fields:

Message Element	Value
Header/Verb	get
Header/Noun	SCEDViolatedConstraints
Header/Source	Market participant ID
Header/UserID	ID of user
Request/StartTime	Start time of interest
Request/EndTime	End time of interest

The corresponding response messages would use the following message fields:

Message Element	Value
Header/Verb	reply
Header/Noun	SCEDViolatedConstraints
Header/Source	ERCOT
Reply/ReplyCode	Reply code, success=OK, error=ERROR or FATAL
Reply/Error	Error message, if error encountered
Payload/	SCEDViolatedConstraints

The structure of SCED violated constraints are described by the following diagram:

SCEDViolatedConstraints Structure

SCEDViolatedConstraint Structure

The following elements are used to report violated constraints:

Name of the constraint
Value that exceeded limit
Defined limit for constraint
Timestamp of violation
Contingency Name
Station name which contingency is from
Station name which contingency is to
Station voltage which contingency is from
Station voltage which contingency is to
Constraint is competitive or not
Violated MW
Constraint ID
Max shadow price

The following is an XML example:

<ns1:SCEDViolatedConstraints xmlns:ns0="http://www.ercot.com/schema/2007-05/nodal/eip/il"
    xmlns:ns1="http://www.ercot.com/schema/2007-06/nodal/ews">
    <ns1:SCEDViolatedConstraint>
        <ns1:name>6485__A</ns1:name>
        <ns1:value>156.8</ns1:value>
        <ns1:limit>156.8</ns1:limit>
        <ns1:shadowPrice>431.39862</ns1:shadowPrice>
        <ns1:timestamp>2017-09-20T10:55:12-05:00</ns1:timestamp>
        <ns1:ContingencyName>SMNHODE8</ns1:ContingencyName>
        <ns1:fromStation>MOSSW</ns1:fromStation>
        <ns1:toStation>PBSES</ns1:toStation>
        <ns1:fromStationKV>138.0</ns1:fromStationKV>
        <ns1:toStationKV>138.0</ns1:toStationKV>
        <ns1:CCTStatus>NONCOMP</ns1:CCTStatus>
        <ns1:ViolatedMW>0.0</ns1:ViolatedMW>
        <ns1:ConstraintID>3.0</ns1:ConstraintID>
        <ns1:MaxShadowPrice>3500.0</ns1:MaxShadowPrice>
    </ns1:SCEDViolatedConstraint>
</ns1:SCEDViolatedConstraints>