Subject: Parallel Flows Task Force (PFTF) Summary - Bill Rust and Charles Yeung
From: [email-masked]
To: [email-masked]
Cc: [email-masked], [email-masked], [email-masked], [email-masked], [email-masked], [email-masked], [email-masked]
Date: Fri, 4 May 2001 05:54:00 -0700 (PDT)

Kevin

Here is a summary of the work of this task force.  Bill Rust has been 
attending  the meetings and I have been closley coordinating our positions.

The PFTF set out to develop a means to capture native load impacts (not 
tagged) in load flow models to ensure that parallel flows resulting from 
native load dispatch are accounted for accurately to assess system security.  
This has largely been ignored in the past since most TLRs hit only non-firm 
PTP transactions.  However, the NERC TLR procedures (in line with FERC OATT) 
requires a pro-rata curtailment of native and network service with Firm 
point-to-point (PTP).  Since more and more TLRs at Level 5 (Firm) have been 
utilized and is expected to rise, providers are being forced by the MIC to 
demonstrate comparability at these TLR levels.  In order to demonstrate 
comparability - a transparent calculation of Native and Network impacts is 
needed.  In past, this was left to the discretion of each control area. 

The task force reviewed 7 methods on how to model native gen to native load 
dispatch.  

These seven methods can be grouped into three categories:
1) Continue with the existing method that does not consider counterflows.
2) Inlcude counterflows for NNL (Native/Network Load) and PTP and assign to 
sink control area.
3) Assign NNL counterflows to the control area and PTP counterflows to the 
purchasing selling entitiy (PSE). 

Each method tries to simulate real-time dispatch realizing that an 
interconnection-wide state estimator is not available nor a nodal dispatch 
model.
 
The simplest methods (group 1) adjust each generator individually to a set of 
load points in its control area and repeats until all the units in the 
control area are accounted for.   The problem for the transmission owners 
with this approach is that the netting effects of the real-time dispatch are 
not captured therfore exaggerating the impacts a control area has on its 
neighbors. Group 1 solutions were rejected because the task force beleived 
that its parent, the Security Subcommittee (Dick Ingersoll member) insisted 
on a new procedure that included counterflows - for security reasons.

The initial proposal to include netted effects (Group 2) allows control areas 
to net NNL flows within the control area and PTP to net flows that are 
grouped by sink control area. Group 2 solutions were rejected because PSEs 
would not get credit for off-setting transactions that sink in other control 
areas, e.g. I have a PTP that sinks in TVA that off-sets a PTP that sinks in 
SOCO. Group 2 solutions would not give credit for this.

The most complex method (group 3) allows the native load dispatch to net 
their impacts with all internal gen-load pairings AND nets the contributions 
of point-to-point tagged transactions by PSE.  This is the most equitable 
solution for the market, however it is the most costly and demanding solution 
for the transmission owner/operators. Group 3 solutions were acceptable to 
all parties because it assigned credit to those who are sponsoring 
transactions that relieve the flow gate loading.

Lately, I have been pushed in NERC activities to make calls that boil down to 
what is fair and equitable between native loads and point-to-point service 
vs. what increased burden and accountability on providers is needed to 
provide for that level of comparability.

We should always hold providers to the higher standard.  That is - it is not 
easy to facilitate market transactions, and yes - real people and real 
dollars are needed to be expended by providers to continue facilitating an 
increasingly complex and evolving marketplace.  Providers cannot be let off 
the hook and be allowed to do what is easy and least cost - this has proven 
over and over to have negative impact on the market.