Operation

Commissioning

Active interface

Operation via web-based user interface

Operation via Modbus

Protocol: TCP/UDP.

Operation via Modbus is the standard method of operation for regular operation.

Configuration, initial commissioning and software update of the system control and the connected modules can be performed via the user interface.

Instructions and information for using Modbus are given mainly in this sub-chapter “Operation via Modbus”. The individual Modbus registers and their description can be found in the Modbus Register Map.

In cases where a more detailed explanation of the procedure via Modbus is required, an additional description for using Modbus is given in the chapter “Operation” of the general description

Power Flow Direction Definition

When reading power value or giving power setpoints,

The positive power direction is defined as below

graph LR A(AC)-->B(Smarten Power 150) B-->C(DC link)

Power factor

Regulating Reactive Power

There are 3 variables in the equation defining power factor:

Where

P is active power,
Q is reactive power.
PF is power factor.

If any two of these variables in this equation are determined, the third one is certain. Usually active power is always controlled by the EMS, making several reactive power regulation modes optional

The register for reactive power regulation has 4 modes that could be applied by demand.

If the converter is configured into constant reactive power mode, the register for regulating PF will be ignored by the inverter. The inverter will control its reactive power in accordance with the set reactive power expected value.

Similarly, if the inverter is configured into constant PF mode, the register for regulating System reactive power will be ignored by the inverter. The inverter will control its PF in accordance with the expected PF value.

It should be highlighted that the value of PF and reactive power have no sign in electric engineering, but inductive reactive and capacitive reactive power is totally different. To identify the characteristic of the reactive power, the registers and setpoints are defined with signs.

Active power/reactive power priority

In order to maintain a stable grid voltage, it is desired that inverters be able to supply or absorb reactive power to/from the grid. One way to achieve this is to have the inverter supply or absorb reactive power in response to fluctuations in grid voltage. Many grid codes are requiring converters to support a Volt/VAr auto-regulation function.

In this mode, the reactive power will be regulated by a curve of reactive power versus grid voltage automatically. The registers or setpoints for regulating System reactive power and PF will be both ignored by the inverter.

In the applications, there must be a conflict on the active power and reactive power setpoints versus the inverter power capacity. Suppose the converter capacity is 150kVA, and the Volt-VAr mode is activated, the EMS is commanding the active power as 120kW discharging but not regulating the reactive power while the available reactive power ability is 90kVA, according to the equation

Where S is the apparent power rating of the inverter.

At this very time, the grid voltage rises and triggers the Volt-VAr algorithm to be 120kVAr lagging (inductive) reactively.

In each mode the converter always takes reactive power setpoint higher priority than active power setpoint, if the sum of squares of the P and Q, is higher than the square of kVA rating, the Q rating will be applied, and the P will be conducted as the function of S and Q.

Specifically, in this case, the inverter will reduce the active discharging power from 80kW to 60kW and absorbs 80kVAr inductive reactive power. There are three modes for regulating reactive power

Constant Power Factor - the reactive power will be designated by PF setpoint and active power setpoint
Constant reactive power - the reactive power will be designated by reactive power setpoint directly
Volt-Var - the reactive power will be designated by the grid voltage, following the curve made by several Volt-VAr (V,Q) points, which are usually defined by deferent grid codes. In Volt-VAr mode, the PCS will NOT response to PF or Reactive power setpoints, but will dynamically generate reactive power depending on the grid voltage.

Transmission of power

Displaying and resetting messages

Overload

To permit load peaks when starting up motors or when starting devices, the modules can be operated in overload operation. This method of operation is permissible only for a short time and is regulated accordingly by the system.

Overload operation is possible only in the following ambient temperature ranges: -5°C to 40°C

Actual values

Process set values

Operation with voltage regulation (grid-forming or grid-following mode)

System configuration

Setting grid codes

Grid codes define rules that generation systems must obey for authorization to connect to the public grid. In particular, these rules regulate behavior in the event of grid fluctuations.

The grid operator determines the behavior of systems in the event of undervoltage, overvoltage and frequency deviation, and also defines the connect and disconnect conditions.

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