ADMS 3.5.1
Energy Losses
Functional Specification
ADMS 3.5.1 Energy Losses
Table of Contents
1. REVISION HISTORY .................................................................................................. 1
2. DEFINITIONS AND ABBREVIATIONS ...................................................................... 2
3. REFERENCES ........................................................................................................... 3
4. INTRODUCTION ........................................................................................................ 4
5. OVERVIEW ................................................................................................................ 5
5.1. Architecture ...................................................................................................... 5
5.2. Input................................................................................................................... 5
5.2.1.
Options .................................................................................................. 6
5.2.1.1. EL Options .............................................................................. 6
5.2.1.2. OL Options .............................................................................. 6
5.3. Output................................................................................................................ 7
5.4. Triggers ............................................................................................................. 7
6. FUNCTIONALITY ....................................................................................................... 8
6.1. Energy Losses .................................................................................................. 8
6.2. Operational Losses ........................................................................................ 10
7. METHODOLOGY ..................................................................................................... 14
7.1. Energy Losses ................................................................................................ 14
7.2. Operational Losses ........................................................................................ 15
8. ERROR MESSAGES................................................................................................ 18
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Table of Figures
Figure 6.1 – Energy Losses in Function Execution Manager ............................................ 8
Figure 6.2 – Energy Losses Options dialog ...................................................................... 9
Figure 6.3 – EL Report window – Overview tab .............................................................. 10
Figure 6.4 – EL Report window – Individual tab .............................................................. 10
Figure 6.5 – Operational Losses in Function Execution Manager ................................... 11
Figure 6.6 – Operational Losses Options dialog ............................................................. 11
Figure 6.7 – OL Report window – Overview tab .............................................................. 12
Figure 6.8 – OL Report window – Individual tab.............................................................. 13
Figure 7.1 – PI results used for OL calculation................................................................ 16
Figure 7.2 – Storing PI results - Simplified diagram ........................................................ 16
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1. REVISION HISTORY
Version
Authors
Date
Comments
1.0
Dejan Vuletić
15-Nov-2014
Initial version
1.1
Dejan Vuletić
15-Nov-2014
Modified structure of
Updated document.
1.2
Branislav Brbaklic
21-Nov-2014
Document Update
1.3
Dejan Vuletić
09-Feb-2015
Document Update
1.4
Ken Zanewich
18-Mar-2015
NA Review and edits
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2. DEFINITIONS AND ABBREVIATIONS
Definition/Abbreviation Description
ADMS
Advanced Distribution Management System
EL
ADMS Energy Losses Application
OL
ADMS Operational Losses Application
FEM
Function Execution Manager
LF
Load Flow
MV
Medium Voltage
PI
Performance Indices
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3. REFERENCES
#
Title
Description
1.
FS Power Applications Infrastructure
Provides functional specification of ADMS
Power Applications global aspects.
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4. INTRODUCTION
The problem with increased levels of power, as well as energy losses is a common problem
in modern utilities, due to the constant increase of power grid loads and need for higher
power quality . The ADMS Losses applications provide a global insight into the
power/energy losses in a utilities entire radial or weakly meshed, balanced or unbalanced
distribution (MV) network, for a specified network state and configuration, for a specified
time period. The ADMS Losses applications are available in two modes: ADMS Energy
Losses (EL) which calculates losses on the basis of simulated load flow calculations and
ADMS Operational Losses (OL) which calculates losses on the basis of data stored in
historical data base during real time system operation.
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5. OVERVIEW
EL&OL provide an assessment of the power/energy losses for a specified calculation area
(the area consists of selected feeders, transformer areas and substations). Based on this,
the application enables the identification of the most critical parts of the network regarding
energy losses.
Having a clear insight into the losses in the considered network, EL&OL provide a basis
for reducing these losses and improving network operation. Reduction of losses not only
means direct cost reductions, but it implicitly means a better voltage profile and balancing
of loads as well.
Loss reduction is a very important goal for development planning. Therefore, EL&OL are
often used as important tools for network planning.
5.1. Architecture
Both EL&OL use a common power application architecture described in the ‘FS Power
Applications Infrastructure’ document [1]. The EL application is dependent on Load Flow
calculations and the OL application is dependent on data stored in the historical data base
(consisting of production real time data regarding customer interruptions).
5.2. Input
Static input data for both EL&OL applications contains the network data model that
includes an appropriate mathematical representation (simulation model) of the network
where the network topology and network elements are prepared for calculations [1]. The
dynamic input data for the EL application includes a specific network load provided by the
user (by mode selection) and the current network configuration.
In addition to the topological state of the network, the input data set for the OL application
includes information about losses, consumption, generation and injected power of circuits
from the past, collected from historical data base. Also, appropriate options related to the
selection of intervals from historical data necessary for energy calculations, needs to be
selected.
Apart from static and dynamic data, the input data sets for both EL&OL include a list of
feeders and transformer areas where losses are to be calculated.
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5.2.1.
Options
5.2.1.1. EL Options
Name
Initial value
Range
Description
Current load Mode,
Mode
with
the
average load for a
specific period,
Detail mode. Time
step for the detail
mode can be:
Load selection
Current
Mode
load 

15 minutes,
30 minutes,

1 hour,

2 hours,

6 hours.
Determines which kind of
mode will be used during the
calculation
Range for the period
selection is [-2 year,
+1 year] considering
the current moment.
5.2.1.2. OL Options
Name
Initial value
Range
Description
Period of
evaluation
Period of one
month (end date
is current date
and start date is
one month ago)
Determines
which
1/1/1900 – Current date
period of time in the past
(Period from history only)
the calculation of losses
will be performed.
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5.3. Output
The main outputs of EL&OL are as follows:

Active/reactive energy losses,

Active/reactive consumed energy,

Active/reactive generated energy,

Active/reactive injected energy.
All results from above are calculated for feeders and transformer areas. Furthermore, EL
provides aggregated results for substations and the entire portion of the network that was
selected. All calculations are followed by user oriented reports.
5.4. Triggers
EL is aimed for what-if analysis. It can be executed upon user request only, in both realtime and simulation modes.
OL can be executed upon user request in both real-time and simulation modes. This
application is dependent on data stored in the historical data base (based on production
real time data regarding customer interruptions). This data is reached from both real time
and simulation contexts in the production environment.
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6. FUNCTIONALITY
6.1. Energy Losses
The OL application is shown in the Function Execution Manager (FEM) by selecting Energy
Losses from the main DMD menu (Figure 6.1). After that, users choose that part of the
network where EL is to be performed. Transformer areas and feeders can also be selected
for the EL calculation.
Figure 6.1 – Energy Losses in Function Execution Manager
The mode used for EL calculation needs to be selected in the Energy Losses Options
dialog (Figure 6.2):

The calculation can be performed for the current load. If EL is used in real-time, the
last estimated load will be considered during the calculation. Otherwise, in simulation
mode, the value used for consumption will be equal to the load specified at the
moment defined as the simulation time,

If the average load is selected, a specific period must be defined. The average load
during a defined period will be determined and sent to the calculation engine, and EL
will be performed for this configuration,

If the detailed mode is selected, a specific period and a time step must be defined.
For additional information on EL modes, refer to Methodology.
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Figure 6.2 – Energy Losses Options dialog
During the EL calculation, results from the Load Flow (LF) and Performance Indices (PI)
applications are used. The most important values are those PI results related to generated,
injected and consumed active (real) and reactive power, as well as calculated active and
reactive power losses. All these results are summarized and presented per circuit (feeder,
transformer area and substation). Given that energy is needed, EL uses proper PI results
(power) and performs multiplication using time intervals in order to obtain EL results
(energy) for circuits (feeders, transformer areas and substations).
EL results are presented in a report and are shown in 2 tabs: Overview and Individual.
The Overview tab (Figure 6.3) contains basic results:

Tables in the upper part of the report present the following results:
o
o

The Active Energy [kWh] graph presents the following results:
o
Injected – Active energy injected in the selected circuit,
Generation – Active energy generated in the selected circuit,
Consumption – Active energy consumed in the selected circuit,
o
Losses – Active energy losses in the selected circuit.
o
o

Active electric energy losses in the selected circuit – WP Losses (kWh, %),
Reactive electric energy losses in the selected circuit – WQ Losses (kVArh, %).
The Reactive Energy [kVArh] graph presents the following results:
o
o
o
o
Injected – Reactive energy injected in the selected circuit,
Generation – Reactive energy generated in the selected circuit,
Consumption – Reactive energy consumed in the selected circuit,
Losses – Reactive energy losses in the selected circuit.
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Figure 6.3 – EL Report window – Overview tab
The Individual tab (Figure 6.4) presents all the above mentioned results in a table.
Figure 6.4 – EL Report window – Individual tab
6.2. Operational Losses
The OL application is shown in FEM by selecting Operational Losses from the main DMD
menu (Figure 6.5). After that, to the user selects circuits (feeders or transformer areas) on
which the OL application is performed.
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Figure 6.5 – Operational Losses in Function Execution Manager
The period of calculation needs to be selected in the Operational Losses Options dialog
(Figure 6.6):
Figure 6.6 – Operational Losses Options dialog
This calculation can be performed for a selected period in the past. The lower time limit
(lowest value for Start) is 1/1/1900. This means that data about losses must be available
for this duration and thus be available in historical database (i.e. previously entered in
from old records). End can be set to a maximal value of the current date or to some date
in the past – but End date must be closer to present than Start.
During the OL calculation, historical results of LF and PI are used. The most important
values are PI results related to generated, injected and consumed active (real) and reactive
power as well as calculated active and reactive power losses. All of these results are
summarized and presented per circuit (feeder, transformer area and substation). Given
that energy is needed, OL uses proper PI results (power) and performs multiplication using
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time intervals in order to obtain OL results (energy) for circuits (feeders, transformer areas
and substations). OL results are actually historical EL results i.e. losses for some period
of the past.
OL results are presented in a report and are shown in 2 tabs: Overview and Individual. The
Overview tab (Figure 6.7) contains basic results:

Tables in the upper part of the report present the following results:
o
o

The Active Energy [kWh] graph presents the following results:
o
o
o
o

Active electric energy losses in the selected circuit – WP Losses (kWh, %),
Reactive electric energy losses in the selected circuit – WQ Losses (kVArh, %).
Injected – Active energy injected in the selected circuit,
Generation – Active energy generated in the selected circuit,
Consumption – Active energy consumed in the selected circuit,
Losses – Active energy losses in the selected circuit.
The Reactive Energy [kVArh] graph presents the following results:
o
Injected – Reactive energy injected in the selected circuit,
Generation – Reactive energy generated in the selected circuit,
Consumption – Reactive energy consumed in the selected circuit,
o
Losses – Reactive energy losses in the selected circuit.
o
o
Figure 6.7 – OL Report window – Overview tab
The Individual tab (Figure 6.8) presents all the above mentioned results a table.
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Figure 6.8 – OL Report window – Individual tab
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7. METHODOLOGY
7.1. Energy Losses
The EL application deals with predicted losses (in the predicted (estimated) system state,
using the LF application) in any user defined period of time. Distribution of losses per
network elements and their grouping by supply elements (substations, transformers,
feeders) provide a clear insight into the network state.
The following modes of the EL application are available:

Current mode – In this mode, the LF application is used only once with the current
state. In this way, energy losses, consumed energy, generation energy and injected
energy for the last hour (equal to powers) are calculated,

Average mode – In this mode, the user selects a time period. The LF application is
used only once with the average state (by losses) in that period. Afterwards, results
are multiplied with the time interval. In this way, energy losses, consumed energy,
generation energy and injected energy for the time period are calculated,

Detail mode – In this mode, the user selects a time period and resolution of LF
calculations triggering.
In detail mode selected time period is divided into sub–periods (according to resolution)
that are considered with the same level of consumption. Typical days are identified in each
sub-period: working day, Saturday, Sunday and holiday. For a working day, at least one
representative is taken (all 5 working days are described with the same set of normalized
daily load profiles) or up to 5 representatives (each of 5 working days is described with
different set of normalized daily load profiles). Numbers of days that are recognized as one
of the typical days are calculated for each sub-period (e.g., a number of Saturdays is
calculated in the sub-period, number of Sundays, etc.). Calculation of losses for one of the
typical days is performed for each specific moment, taking into account the calculation time
step (the time step is configurable: 15 minutes, 30 minutes, 1, 2 or 6 hours). For example,
for 1 hour time step, the calculation will be performed 24 times (for each hour during the
24 hours period). The consumption for every hour is taken from provided daily load curves.
In this way, the value of consumption is provided at every consumption point. This data is
used as the input for the LF application. The LF application calculates the network state
(e.g., voltage in every node of the distribution system, active/reactive power flows). The
network state is the input for the PI calculation. This application provides power losses,
while energy losses are calculated assuming that the given state lasts for the next hour
(for a 1 hour time step for example). Calculated losses for each element are summarized
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for the entire period (24 calculation results for 1 hour time step example). This calculation
is performed for all typical days. Losses per each of the typical days are multiplied by the
number of the days in the sub-period and the calculated result is added to the sum for subperiod losses. Finally, total period losses are calculated by adding sub-period losses.
Obviously, a significant number of calculations have to be performed for the EL application.
Therefore, the request for extremely fast and efficient calculations makes sense. A branch
oriented technique is the only one that can fulfill this request and this technique is applied
in EL.
7.2. Operational Losses
The OL application deals with historical losses data for some parts of the network, for any
user defined period of time in the past. During the use of ADMS in the real time production
environment, the load flow application followed by the performance indices calculation is
triggered frequently. These applications could be triggered as part of the state estimation
application (either periodically or driven by a significant measurement value change),
triggered by a topology state change or even on demand. Each time the LF and PI are
triggered, the results of these applications are provided to the system. In order to be
available for additional analysis, some of these results are stored in the historical data base
for further usage. The Load Flow Historical Configuration can be used for selecting those
parameters which are going to be stored in the historical data base. By default, PI results
that are needed by the OL application are always stored in the historical data base (they
are mandatory). These PI result parameters are the real and reactive consumption power,
losses, generation and injected power of feeder and transformer area circuits (Figure 7.1).
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Figure 7.1 – PI results used for OL calculation
This means that each time that LF and PI are triggered (and calculated) during their use
in the production real time environment, proper results (i.e. the power) will be stored for
each feeder and transformer area in the network.
t1
t2
t3 t4
tn
time line
PI res1
PI resn
Historical data base
Figure 7.2 – Storing PI results - Simplified diagram
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When the OL application is triggered, it uses a query to pick all the above mentioned values
recorded in the historical data base and by calculating integral values it provides the:

Active/reactive energy losses,

Active/reactive consumed energy,

Active/reactive generated energy,

Active/reactive injected energy.
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8. ERROR MESSAGES
Message
Severity
Description
Results are questionable because
Warning
Load Flow results are questionable.
During the EL calculation, some of the
LF calculation(s) provide questionable
results.
Results are bad because Load
Warning
Flow results are bad.
During the EL calculation, some of the
LF calculation(s) provide bad results.
Note that these messages are related to the EL mode. OL will present only those error
messages related to data base deployment issues.
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