IEEE Power & Energy Magazine - September/October 2017 - 3

DIgSILENT PowerFactory for

Quasi-Dynamic Simulation
Analysing and Optimising Microgrids
Quasi-Dynamic Simulation (QDS) is a suitable tool for addressing the impact
of high penetration of distributed generation, for example voltage variations,
reverse power flow, reactive power and voltage control issues.
QDS assumes that changes take place sufficiently slowly that the system can
be considered to be in steady-state at each simulation point. QDS has been
designed to run several different load flow simulations with a series of operating conditions, achieved by modelling the network dependence on time.
Quasi-Dynamic Simulation Language (QDSL) is based on DPL (DIgSILENT Programming Language) and offers the possibility to implement all types of load
flow, slow reacting controllers or other steady-state behaviour. PowerFactory
offers a seamless integration of QDSL models within the load flow calculation and the quasi-dynamic simulation engines. This means that once a QDSL
model is implemented it is available not only for load flow and quasi-dynamic
simulations but also for any other command which makes use of these.

Figure: QDSL models - Simulation Procedure
tk+1=tk+step

tk

tk+1
time

Intialisation
QDSL Models

Selected Key Applications

Control
Quasi-Dynamic

Analysis and optimisation of Microgrids and Smart Grids;
integration and analysis of distributed energy resources,
energy storage (batteries) and electric vehicles

control
change

Equations
Load flow
convergent
Newton
Rapson loop

Control
Quasi-Dynamic

Equations
Quasi-Dynamic

Study the impact of Maintenance Schedules, Network Variations and Operation Scenarios
Analysis and integration of data from smart meters; statistical analysis of monitored variables

convergent
control loop

Control
Load flow
0,008

Load flow Model

Integration
of states

control
change

[MW]
0,006

0,004

0,003

0,002

0,000

0,000

-0,003

-0,002
00:00:00

04:47:00

09:34:00

14:21:00

19:08:00

23:55:00

-0,006
00:00:00

PVBattery_001: Load: Total active power
PVBattery_001: PV: Generator active power

04:47:00

09:34:00

14:21:00

19:08:00

23:55:00

PVBattery_001: Injection in the network without Battery
PVBattery_001: Injection in the network with Battery installation
PVBattery_001: Load: Total active power
PVBattery_001: PV: Generator active power

0,983

110,00

[p.u.]

[%]

0,980

90,00

0,977

70,00

0,974

50,00

0,971

0,968
00:00:00

Planning and sizing of distributed generators and energy
storage; mitigation of the impact of a large amount of PV

0,009

[MW]
0,006

Impact Analysis E-Mobility, e.g. maximum charging capacity
that the system can handle with existing controls
Predict service lives of mechanical devices like transformer
tap changer based on total number of operations
Allows users to verify steady state of the network under
different conditions in a given time period

30,00

04:47:00

09:34:00

14:21:00

19:08:00

FN_285676393: Voltage, Magnitude
Summary Grid: Minimum voltage of all terminals

23:55:00

10,00
00:00:00

04:47:00

09:34:00

14:21:00

19:08:00

23:55:00

PVBattery_001: State of charge

For more Information about DIgSILENT PowerFactory visit www.digsilent.com.

Optimal placement of storage systems
http://www.digsilent.com
Table of Contents for the Digital Edition of IEEE Power & Energy Magazine - September/October 2017
