This document describes the SINAMICS PCS (Power Conversion System) simulation model, which is a simulation model of a power generating unit (PGU) designed for use in MATLAB/Simulink®. The model is compliant with VDE application rule 4110 (VDE-AR-N 4110) and is intended for simulating the behavior of power generating units in various grid conditions.

Function Description

The SINAMICS PCS simulation model provides a comprehensive representation of a power generating unit, enabling users to simulate its performance and interaction with the grid. The PGU itself comprises several key components:

Active Interface Module (AIM) of the SINAMICS S120 series: This module handles the active power exchange with the grid.
Active Line Module (ALM) of the SINAMICS S120 series: This module manages the reactive power and voltage control.
An energy source connected to the device DC connection: This represents the primary energy input to the system.
A hardware-related closed-loop control of the PGU: This control is realized in the CU320-2 Control Module, ensuring precise and stable operation.

The SINAMICS firmware includes a DCC (Drive Control Chart) to implement the requirements of VDE-AR-N 4110. The simulation model incorporates various features to accurately reflect the PGU's behavior under different operating conditions:

Grid reactor and inverter: These components are fundamental to the power conversion process.
Closed-loop control of the active and reactive current in undisturbed operation and for dynamic grid faults: This ensures stable current control during normal operation and robust response to grid disturbances.
Closed-loop control of the DC voltage: Maintains a stable DC link voltage within the converter.
Closed-loop reactive power control: Allows for precise control of reactive power exchange with the grid.
Direct setpoint input in cos phi closed-loop control/Q(U)/Q(P) operating mode: The model supports various operating modes for reactive power control, with the direct setpoint input being a key feature.
Controlled reduction of the active power for overfrequency conditions and when specified by the grid operator: This feature ensures compliance with grid codes during overfrequency events and allows for external control of active power.
Grid protection and/or grid monitoring: The model includes functionalities to simulate grid protection mechanisms, ensuring safe operation.

The PGU simulation model addresses the following VDE4110 application scenarios:

Steady-state response in undisturbed operation: Simulates the PGU's behavior under normal, stable grid conditions.
Shutdown response in the event of an undervoltage condition: Evaluates the PGU's reaction and shutdown procedure during voltage sags.
Shutdown response in the event of an overvoltage condition: Assesses the PGU's response to voltage swells.
Shutdown response in the event of an underfrequency condition: Simulates the PGU's behavior during frequency drops.
Shutdown response in the event of an overfrequency condition: Analyzes the PGU's response to frequency increases.
Response for steady-state grid support: Models the PGU's ability to provide continuous support to the grid.

The model also simulates various derived variables and control mechanisms:

Reactive power specified by the grid operator: Allows external control of reactive power.
Maximum permissible active power specified by the grid operator: Enables external limitation of active power.
Controlled reduction of the active power fed back for an overfrequency condition: Simulates active power curtailment during high frequency events.
Dynamic grid support for 3-phase (symmetrical) grid voltage dips: Models the PGU's response to symmetrical voltage sags.
Dynamic grid support for 2-phase (asymmetrical) grid voltage dips: Models the PGU's response to asymmetrical voltage sags.

The PGU simulation model can be integrated into an electrical network simulated using Simscape. This allows for comprehensive system-level simulations, including the interaction of multiple PGUs operating in parallel.

Important Technical Specifications

The simulation model is designed to represent a PGU with specific electrical characteristics. Key parameters and their value ranges are defined as follows:

Constants:

Grid frequency: 50 Hz
Rated reactive power of the PGU (under excited): 190 kVAr
Rated reactive power of the PGU (over excited): 280 kVAr

Parameters:

Un: Rated grid voltage (phase-to-phase): 3 AC 250 ... 500 V
In: Rated current of the PGU: 500 ... 1083 A

Derived variables:

Pn: Rated active power of the PGU: Pn = Un × In × 1.732 / 1083 = 217 ... 940 kW
Qn: Rated reactive power of the PGU: Qn = Pn × 0.33 = 72 ... 287 kVAr
QUe: Max. reactive power of the PGU for underexcitation: QUe = Qn - 40 kVAr = 32 ... 247 kVAr
QUe: Max. reactive power of the PGU for overexcitation: QUe = Qn + 50 kVAr = 122 ... 337 kVAr

The model includes various inputs and outputs, each with a defined value range:

Inputs:

V_rated: Rated grid voltage in V (250 ... 500)
I_rated: Rated current of the PGU in A (500 ... 1083)
On/Off: Power generating unit is switched on or switched-off (0: off, 1: on)
P_ref_PLC: Percentage limiting of the active power that is fed back (0 ... 1)
Q_ref_EVU: Percentage setpoint for the reactive power that is fed back (-1 ... 1)
k_FRT: The k factor for the reactive current droop in the case of an FRT (0 ... 10)
LGSM (limited grid support mode): The limited grid support mode is activated (> 0)
P(f) gradient: The gradient of active power adjustment P(f) for overfrequency and underfrequency (0.4 ... 1.0)
Prot_Parameter: Relative limit values and response times for grid monitoring (various voltage and frequency limits with corresponding delay times, e.g., U>>_Limit, U<<_Limit, f>>_Limit, f<<_Limit).

Outputs:

P_EZE [kW]: Indicates the rated active power of the power generating unit (> 0 kW)
Q_EZE [kVAr]: Indicates the rated reactive power of the power generating unit (> 0 kVAr)
Status_On/Off: Indicates the status of the power generating unit (0: off, 1: on)
Sta-tus_Protection: Indicates whether grid monitoring detected a fault and shut down (0: no grid fault, 1: grid fault detected)
I_b_RMS+: Rms value of the reactive current in the positive phase sequence system (not limited, in A)
I_w_RMS+: Rms value of the active current in the positive phase sequence system (not limited, in A)
I_b_RMS-: Rms value of the reactive current in the negative phase sequence system (not limited, in A)
I_w_RMS-: Rms value of the active current in the negative phase sequence system (not limited, in A)
I1, I2, I3: Instantaneous value of the phase current conductor (not limited, in A)
V_L1, V_L2, V_L3: Actual phase voltage, conductor (not limited)

Usage Features

The SINAMICS PCS simulation model is designed for use within the MATLAB/Simulink® environment, specifically with MATLAB/Simulink® R2018b or later. The model is provided as a protected PGU model, meaning its internal structure is encapsulated, and parameter changes are not required at the model itself. All configuration settings are made at the signal inputs of the protected model.

Model Files:

EZE_SINAMICS_PCS.slxp: This file contains the protected PGU model.
Netz_SINAMICS_PCS_Parallel.slx: This file contains a system model with three PGUs operating in parallel, connected to a single power supply grid. This allows for simulating complex scenarios involving multiple power generating units.

Importing and Using the Model:

Open the model: Double-clicking on the system model file (Netz_SINAMICS_PCS_Parallel.slx) will open it in MATLAB/Simulink®.
Configure the simulation: The simulation parameters can be adjusted through the "Configuration Parameters" dialog in Simulink. Key settings include:
- Solver type: ode23tb (stiff/TR-BDF2) is recommended for variable-step simulations.
- Max step size: 0.01
- Min step size: auto
- Relative tolerance: 1e-4
- Absolute tolerance: 0.01
- Solver reset method: Fast
- Shape preservation: Disable All
- Number of consecutive min steps: 1
- Solver Jacobian method: auto
- Zero-crossing control: Disable All
- Simscape Solver Configuration: For Simscape, "Backward Euler" is the recommended solver type with a fixed step size.
Parallel operation: The system model facilitates the simulation of multiple PGUs in parallel, connected to a power supply grid modeled using Simscape. This is particularly useful for evaluating the collective behavior of power generating units in a microgrid or larger power system.
FRT processes in grids with low short-circuit power ratings: The model includes measures to improve the stability of the simulation during Fault Ride Through (FRT) processes in weak grids:
- Installation of a PT1 element with a time constant of 5 ms for smoothing very steep voltage changes behind the source for the line voltage amplitude.
- Decoupling of the power generation units from the supply model by placing a memory block in front of each phase current source in the Simscape supply model.

Deactivating the simulation model: To deactivate a power generating unit model in a project, select it using the right-hand mouse key and then select "Comment out" in the shortcut menu.

Maintenance Features

The document primarily focuses on the simulation model itself rather than physical device maintenance. However, it emphasizes the importance of using certified personnel for any work related to the product system. Qualified personnel are defined as those who are familiar with the documentation, installation, assembly, commissioning, operation, and maintenance of the products and components, and who are capable of identifying risks and avoiding potential hazards.

Safety Notes: The manual includes various safety notes to ensure personal safety and prevent damage to property. These notes are highlighted with safety alert symbols (DANGER, WARNING, CAUTION, NOTICE) and must be strictly observed.

DANGER: Indicates that death or severe personal injury will result if proper precautions are not taken.
WARNING: Indicates that death or severe personal injury may result if proper precautions are not taken.
CAUTION: Indicates that minor personal injury can result if proper precautions are not taken.
NOTICE: Indicates that property damage can result if proper precautions are not taken.

Industrial Security: Siemens products and solutions are designed to protect against unauthorized access to plants, systems, machines, and networks. Users are responsible for implementing appropriate security measures, including firewalls, network segmentation, and regular updates. The document recommends:

Keeping the software up to date.
Incorporating the automation and drive components into a holistic, state-of-the-art industrial security concept.
Making sure that all installed products are included in the integrated industrial security concept.
Protecting storage media from malicious software.
Checking all security-related settings once commissioning has been completed.
Using secure services or VPNs from dependable and trustworthy sources.
Implementing Siemens Industry Online Service and data storage media provided (e.g., documentation DVD).

Support: Siemens provides comprehensive support for its products, including the SINAMICS PCS simulation model. Users can access:

Technical Support: Available via phone and internet for Europe/Africa, America, and Asia/Pacific regions.
Siemens Industry Online Support App: Provides access to over 300,000 documents for Siemens Industry products, troubleshooting when faults develop, and expanding a system or planning a new system.
Technical Forum: Access to FAQs, application examples, manuals, certificates, and product announcements.
Internet address: www.siemens.com/sinamics-pcs for general information.
IndustryMall: www.siemens.com/industrymall for product information and ordering.

Certifications: The SINAMICS PCS simulation model and related products comply with various certifications:

EC Declaration of Conformity with reference to the low voltage directive.
EC declaration of conformity with reference to the EMC directive.
Certificate according to VDE-AR-N 4110.

This ensures that the simulation model accurately reflects the behavior of a certified and compliant power generating unit.

Siemens SINAMICS PCS - Page 24

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