Issues

NPRR562

Summary
Action
Voting Record
Background
Key Documents

Summary

Title	Subsynchronous Resonance
Next Group
Next Step
Status	Approved on 06/13/2017
Effective Dates	09/14/2017 All sections except for Section 3.22.1.4 04/09/2018 Section 3.22.1.4

Action

Date	Gov Body	Action Taken	Next Steps
06/13/2017	BOARD	Approved
05/25/2017	TAC	Recommended for Approval	Revision Request Consideration
04/13/2017	PRS	Recommended for Approval	Revision Request Consideration
03/09/2017	PRS	Recommended for Approval	PRS for Impact Analysis review
06/11/2014	PRS	Deferred/Tabled	PRS for consideration
05/15/2014	PRS	Deferred/Tabled	PRS for consideration
09/19/2013	PRS	Deferred/Tabled	PRS for consideration

Date

Gov Body

Action Taken

Next Steps

06/13/2017

BOARD

Approved

05/25/2017

TAC

Recommended for Approval

Revision Request Consideration

04/13/2017

PRS

Recommended for Approval

Revision Request Consideration

03/09/2017

PRS

Recommended for Approval

PRS for Impact Analysis review

06/11/2014

PRS

Deferred/Tabled

PRS for consideration

05/15/2014

PRS

Deferred/Tabled

PRS for consideration

09/19/2013

PRS

Deferred/Tabled

PRS for consideration

Voting Record

Date	Gov Body	Motion	Result
06/13/2017	BOARD	Approved NPRR562 as recommended by TAC in the 5/25/17 TAC Report.	Passed
05/25/2017	TAC	To recommend approval of NPRR562 as recommended by PRS in the 4/13/17 PRS Report.	Passed
04/13/2017	PRS	To endorse and forward to TAC the 3/9/17 PRS Report, as revised by PRS, and Revised Impact Analysis for NPRR562 with a recommended priority of 2017 and rank of 1990.	Passed
03/09/2017	PRS	To recommend approval of NPRR562 as amended by the 3/3/17 ERCOT comments	Passed
06/11/2014	PRS	To table NPRR562.	Passed
05/15/2014	PRS	Table NPRR562 for one month.	Passed
09/19/2013	PRS	To table NPRR562.	Passed

Date

Gov Body

Motion

Result

06/13/2017

BOARD

Approved NPRR562 as recommended by TAC in the 5/25/17 TAC Report.

Passed

05/25/2017

TAC

To recommend approval of NPRR562 as recommended by PRS in the 4/13/17 PRS Report.

Passed

04/13/2017

PRS

To endorse and forward to TAC the 3/9/17 PRS Report, as revised by PRS, and Revised Impact Analysis for NPRR562 with a recommended priority of 2017 and rank of 1990.

Passed

03/09/2017

PRS

To recommend approval of NPRR562 as amended by the 3/3/17 ERCOT comments

Passed

06/11/2014

PRS

To table NPRR562.

Passed

05/15/2014

PRS

Table NPRR562 for one month.

Passed

09/19/2013

PRS

To table NPRR562.

Passed

Background

Status:	Approved
Date Posted:	Aug 12, 2013
Sponsor:	ERCOT
Urgent:	No
Sections:	2.1, 2.2, 3.1.1, 3.1.5.11, 3.22 (new), 3.22.1 (new), 3.22.1.1 (new), 3.22.1.2 (new), 3.22.1.3 (new), 3.22.1.4 (new), 3.21.2 (new), and 3.22.3 (new)
Description:	This Nodal Protocol Revision Request (NPRR) creates new requirements for the identification, study, mitigation of, and protection against Subsynchronous Resonance (SSR).
Reason:	SSR is a potentially harmful phenomenon involving coincident oscillation between two or more Transmission Elements or Generation Resources at frequencies lower than the normal operating frequency (60 Hz) of the ERCOT System. The ERCOT System has recently become more vulnerable to SSR because of the introduction of series capacitors for voltage support, although other Transmission Elements (including poorly tuned power electronic devices) and generator control systems can also create SSR. Without proper mitigation, SSR can quickly destroy resonating Transmission Elements and/or Generation Resources and lead to cascading Outages. It is therefore essential to carefully study and mitigate this risk. This NPRR is intended to create a process for investigating and addressing SSR risk and to clarify the responsibilities of the various Entities affected.