Sequence Data, Power Flow & Transient Stability (PF & TS)

MSRATF - July 10, 2013

Joe Seabrook

NERC MOD-B Development (May 9, 2013)

• http://www.nerc.com/pa/Stand/Pages/MODBInformalDevelopmentProjectRF.aspx

MOD-B Proposed Approach (May 9, 2013)

Proposed single modeling standard to combine and replace MOD-010 through MOD-015

• Requirement R1: provide steady-state, dynamics, and short circuit data to Planning Coordinator(s) and Transmission Planner(s) according to the data requirements specified in Attachment 1 and other criteria.

• Attachment 1: Specifies a three column detailed matrix of data requirements for steady-state, dynamics, and short-circuit data

MOD-B Proposed Approach (May 9, 2013)

Proposed single standard (R2): • Requirement R2: Provides a requirement for

entities that submit data to provide correct data – Covers data sufficiency, usability, consistency, and

accuracy – Tool for PC or TP in collecting data – Does not obligate a process to check/confirm data

• Uses format similar to MOD-26-1 requirements (see, e.g., MOD-26-1, Requirement R3)

MOD-B Proposed Approach (May 9, 2013)

Proposed single standard (R3): • Requirement R3: To facilitate creation of interconnection-specific

models, a requirement for Planning Coordinator to submit data collected under Requirement R1 according to a (proposed) NERC list of modeling organizations (which are the organizations that currently exist)

• Intended to create clear expectation that each Planning Coordinator will provide the data they collect under Requirement R1 according to an interconnection-specific process

• Recognizes the differences among interconnections in model building process, but creates obligation for PC to provide the data in a manner that accounts for those differences.

• Replaces MOD-014 and MOD-015

MOD-B Attachment 1 (June 17, 2013 conference)

MOD-B Attachment 1 (June 17, 2013 conference)

1. Positive Sequence Data – provide for all applicable elements in column “steady-state”

2. Negative Sequence Data – provide for all applicable elements in column “steady-state”

3. Zero Sequence Data – provide for all applicable elements in column “steady-state”

Bus, Generator, Transmission line, Transformer (include connection type)

4. Mutual Line Impedance data

Resistance, Reactance, Mutual Coupling Locations

Sequence Data in Transient Stability

• WECC TSS/MSRATF - Represent the response of simulation programs to fault conditions through Relay and RAS models– TS fault simulation historically has been

through pre-determined fault impedances and expected relay response.

– Relay and RAS models will require fault detection and appropriate clearing

– Will include all NERC standard faults (3Φ and 1Φ)

Sequence Data in Transient Stability

• Negative and Zero sequence data is network data; R, X, B, connections

• Machine models are + Sequence – Include features to approximate – and 0

sequence, like gen braking, or 1Φ motors

• Simulation programs use sequence data to calculate fault currents in PF

• Fault currents needed in TS

Sequence Data in Transient Stability

• In TS, the + sequence network is solved each time step.

• For Unbalanced Faults require – Negative and zero sequence currents at each

time step – TS models of relays that trip breakers on

negative and zero sequence currents• Common example: Directional zero sequence

inverse time over-current relay – used for 1Φ faults

Sequence Data in Transient Stability

• Simulation Programs would solve negative and zero sequence networks at each time step

• Would provide access to sequence currents and voltages for relay actions

• Would provide decaying fault currents from TS generator models and inverse time over-current relay responses