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meteocontrol Power Control

Operating Manual

Version 20131213

meteocontrol Power Control

Copyright

Copyright for this manual remains with the manufacturer. No part of this manual may

be reproduced or edited, duplicated or distributed using electronic systems without

written permission from meteocontrol GmbH.

Compensation shall be payable in the event of any copyright infringements.

All brand names mentioned in this manual are the property of their respective

manufacturers and are hereby acknowledged.

Contact data

The manufacturer of the device described in this documentation is:

meteocontrol GmbH

Spicherer Str. 48

D-86157 Augsburg

Tel.: +49 (0) 821 / 3 46 66-0

Web: www.meteocontrol.de

Technical support:

Tel.: +49 (0) 821 / 3 46 66-88

Fax: +49 (0) 821 / 3 46 66-11

E-mail: [email protected]

Details regarding the manual

The original operating manual is written in German. All other language versions are

translations of the original operating manual and are hereby identified as such.

© 2013 meteocontrol GmbH

All rights reserved.

All information in this operating manual has been compiled and checked with the

greatest care and diligence. Nevertheless, the possibility of errors cannot be entirely

excluded. meteocontrol GmbH therefore cannot accept any liability for errors or any

circumstances resulting from errors.

Subject to technical alterations.

meteocontrol Power Control 1| 34

Contents 1. General notes ..............................................................................................................2

1.1 Safety instructions ............................................................................................... 2 1.2 Warning symbols ................................................................................................. 2 1.3 Additional information .......................................................................................... 2 1.4 Text display .......................................................................................................... 3

2. Notes on using the operating manual ...........................................................................4 2.1 Warranty and liability ............................................................................................ 5

3. Technical description ...................................................................................................6 3.1 Grid feed-in management requirements ............................................................... 6 3.2 meteocontrol Power Control requirements .......................................................... 6 3.3 meteocontrol Power Control functionality ............................................................ 7 3.4 Power Control Unit functionality ........................................................................... 7 3.5 Power Control with PCU+ functionality ................................................................ 8 3.6 Power Control without PCU+ functionality ........................................................... 9 3.7 Functions ........................................................................................................... 10

4. Power Control device configuration ............................................................................ 11

5. meteocontrol Power Control configuration.................................................................. 11 5.1 WEB’log definition as master ............................................................................. 11 5.2 WEB`log definition as slave ................................................................................ 12 5.3 Power Control system data ................................................................................ 13 5.4 Power control procedures for the meteocontrol Power Control ......................... 14 5.5 Active power procedure ..................................................................................... 18 5.5.1 P(DI) ................................................................................................................... 18 5.5.2 P(AI) ................................................................................................................... 19 5.5.3 P Fix ................................................................................................................... 20 5.5.4 P(DI) internal ...................................................................................................... 20 5.6 Reactive power procedure ................................................................................. 21 5.6.1 Cosφ (DI) ............................................................................................................ 21

5.6.2 Cosφ (AI) ............................................................................................................ 22 5.6.3 Cosφ Fix ............................................................................................................. 23 5.6.4 Cosφ (P) ............................................................................................................. 23 5.6.5 Cosφ (U) ............................................................................................................. 24 5.6.6 Q(DI) .................................................................................................................. 25 5.6.7 Q(AI) ................................................................................................................... 26 5.6.8 Q fix ................................................................................................................... 27 5.6.9 Q(U) ................................................................................................................... 27 5.6.10 Inverter cosφ (P) ................................................................................................. 28 5.6.11 Inverter Q(U) ...................................................................................................... 28 5.7 Enabling Power Control ...................................................................................... 29 5.8 Power Control status.......................................................................................... 29 5.9 Power Control settings via the data logger display ............................................. 30

6. Power quality analyser ............................................................................................... 31

7. Grid feed-in management overview ............................................................................ 32

8. List of figures ............................................................................................................ 33

2| 34 meteocontrol Power Control

1. General notes

1.1 Safety instructions

Safety instructions warn of dangers when using the devices and explain how they can

be avoided.

The safety instructions are classified according to the severity of the risk and are

subdivided into three groups:

DANGER

Imminent danger

– Failure to comply with the warning notice will lead to an imminent risk of death

or serious physical injury!

WARNING

Possible danger

– Failure to comply with the warning notice may lead to a risk of death or serious

physical injury!

CAUTION

Hazard with a risk of material damage

– Failure to comply with the warning notice may lead to minor injuries!

ATTENTION

Hazard with a risk of material damage

– Failure to comply with the warning notice will lead to material damage!

1.2 Warning symbols

Particular dangers are highlighted using warning symbols.

RISK OF ELECTRIC SHOCK

Electric shock hazard! Danger to life and limb!

– Failure to comply with the warning notice will lead to an imminent risk of

serious injury or death.

1.3 Additional information

This symbol can be found next to notes, additional information and tips.


1.4 Text display

Emphasised points are shown in bold and indicate important information.

Lists are shown with bullet points (level 1) and dashes (level 2):

List 1

Point A

Point B

List 2

Instructions describe steps which are to be carried out in the given order.

1. Instruction 1

2. Instruction 2

Result of the operation

Button names are shown in capitals and in "QUOTATION MARKS".

In figures, item numbers are used to indicate components.

The legend with item numbers and descriptions of the components are shown below

the figure. Alternatively, direct references to components are made in the text.


2. Notes on using the operating manual This description is designed to ensure that the WEB’log, PCU and PCU+ devices

function properly. It contains important information and safety notes to help you use

the devices correctly, economically and in the intended manner.

The description helps to avoid dangers, to reduce repair costs and downtimes, and to

increase the reliability and operating life of the devices.

This operating manual describes the additional Power Control functions and,

specifically, the power control procedures.

DANGER

Danger owing to improper handling of the devices

- The staff responsible for the installation, operation and maintenance of the

system must have read and understood this operating manual before the

devices can be configured and used safely!

- If necessary, the description and documents must be available at all times.

meteocontrol GmbH accepts no liability for personal injury, damage to property, or

system malfunctions and their consequences, insofar as these result from non-

observance of this operating manual.

The manual is continually updated. The most up-to-date version of this description can

be found on our internet page www.meteocontrol.de


2.1 Warranty and liability

Details of the scope and form of the warranty as well as the warranty period are given

in the meteocontrol GmbH General Terms and Conditions.

meteocontrol rejects any liability for damage arising from the non-observance of the

operating manual.

This applies, in particular, for damage from:

Unintended use

Faulty operation

Wrongly chosen materials and tools

Faulty or non-executed maintenance and repairs

With Power Control, meteocontrol GmbH accepts no liability for events and

occurrences outside of its control, such as:

the correctness of control commands given by an energy supply company or failure

to implement control commands that have been passed on

hardware and/or software faults on the part of the system operator

switching processes on consumer end.

Any liability for damage caused by such events and occurrences, such as lost

profits, grid instability, damage to parts of the customer's system, for instance of an

inverter, shall remain expressly excluded.


3. Technical description Power Control is a system for controlling and managing different operating parameters

of PV systems (such as reactive and active power).

3.1 Grid feed-in management requirements

As the proportion of solar power in relation to overall power production increases, it

becomes increasingly necessary for PV system operators to become actively involved

in grid feed-in management. This means it must be possible to reduce feed-in power

and play a role in compensating for the reactive power in the grid as stipulated in the

EEG (German Renewable Energy Law), the Medium Voltage Directive, the

Transmission Code and VDE AR-N 4105.

In view of this, the system operators must fulfil the following requirements:

They must be able to reduce the feed-in power of systems by remote control or

disconnect systems from the grid entirely.

They must be able to reduce the reactive power in the grid by reactive power

compensation.

3.2 meteocontrol Power Control requirements

It is recommended that you clarify the following requirements of the grid operator,

inverter manufacturer and system operator for Power Control in the system planning

phase:

Procedures according to which the requirements of the grid operator are

implemented, resulting in control values for the inverters.

Procedures that are supported by the WEB`log for the inverter types used

(inverter drivers).

Interfaces used for the grid operator's remote control and monitoring systems.

Characteristic requirements for the power control mechanism made by the

system operator:

If difficulties regarding these requirements arise or the necessary configuration

options are not available, consult your meteocontrol contact in sales or system

planning/system start-up.


3.3 meteocontrol Power Control functionality

Basic function:

The requirements for power reduction and control are given by the grid operator

and carried out via a selected interface (digital, analogue) by the PCU, PCU+ or

WEB`log inputs.

The control values are determined from the requirements in accordance with

configurable rules. The rules can be defined in accordance with the requirements.

Feedback to the grid operator is optionally provided.

The control values are set on the inverter within a response time as required by the

grid operator.

The grid operator receives a message about the control value set on the inverters.

3.4 Power Control Unit functionality

The Power Control Unit (PCU) and the Power Control Unit + (PCU+) are intelligent,

high-performance modules which expand the functions of the WEB‘log by adding

reactive power control.

This ensures efficient control of the active and reactive power in photovoltaic systems.

General function:

The PCU receives the requirements from the grid operator's remote control and

monitoring system via its inputs.

The PCU prepares the requirements and forwards them to the WEB`log.

The WEB`log establishes the control values and sends them to the inverters.

No PCU is required to achieve a reduction in active power via four potential-free

contacts and without feedback to the grid operator. The corresponding procedures

(referred to as P(DI) internal and P (fix)) can be implemented with the WEB’logs

BASIC, LIGHT+ 20 and PRO unlimited via the digital inputs.

Likewise, no PCU is required for reactive power procedures defined via a characteristic

curve.

On the following pages, meteocontrol Power Control functions are presented with and

without a PCU. The way in which the requirements for active and reactive power

issued by the grid operator reach the inverters is depicted clearly.


3.5 Power Control with PCU+ functionality

Fig. 1: PCU<->Power Control functionality

(1) Grid operator (7) WEB`log PRO as slave

(2) Public grid (8) Inverter

(3) Ripple control receiver (9) Internet

(4) Power Control Unit (PCU) (10) Web portal

(5) WEB`log PRO as master (11) Power requirements report

(6) Ethernet switch


3.6 Power Control without PCU+ functionality

Fig. 2: Power Control functionality

(1) Grid operator (6) WEB`log slave

(2) Public grid (7) Inverter

(3) Ripple control receiver (8) Internet

(4) WEB`log master (9) Web portal

(5) Ethernet switch (10) Power requirements report


3.7 Functions Power control

Active power procedure (P procedure)

With the internal inputs of the WEB`log PRO unlimited, only the active

power procedure can be carried out via digital requirements.

Active and reactive power procedures (P/Q/cosφ procedures)

With the PCU, various active and reactive power procedures can be

selected and configured.

Master functions

In larger systems with several WEB`log PRO Unlimited devices, a WEB`log

assumes the master function.

The master receives the requirement values from the grid operator. The

information is forwarded to all WEB`log slaves or to the configured IP addresses

in the form of a broadcast via the Ethernet.

Power requirements change message

When changing the power requirements, the WEB`log PRO Unlimited

informs one or more recipients via the reporting route configured. The

message contains information on the time of changing and the required

power level.


4. Power Control device configuration Configuration of the Power Control Unit is carried out on the WEB’log websites. The

PCU configuration website is used to configure the Power Control Unit required for the

majority of power control procedures of the meteocontrol Power Control. The site can

be accessed via the menu item Admin Measurement > Power Control > PCU

Configuration.

For the corresponding configuration settings, please see the respective PCU or PCU+

operating manual. Up-to-date versions of the operating manuals are available for

downloading on our website.

5. meteocontrol Power Control configuration Configuration of the power control procedures of the meteocontrol Power Control is

carried out on the WEB’log websites. First, a computer must be connected to the

WEB'log via Ethernet. Afterwards the WEB'log home page can be addressed in the

web browser. Use the selection "Professional mode" and you log in to the admin area

via the General > Login menu. The standard password is: “ist02“.

The configuration is now carried out in the Admin Measurement > Power Control >

General Configuration menu. The individual steps are listed in order so that they can be

carried out consecutively.

5.1 WEB’log definition as master

With this selection, the WEB’log master defines the power control procedures and, if

desired, sends the parameters to the WEB’log slaves. The following figures show the

possible settings for the master:

Fig. 3: WEB`log master with broadcast to all slaves

Fig. 4: WEB`log master without slaves

Fig. 5: WEB`log master with slave groups


5.2 WEB`log definition as slave

With this selection, the data logger receives the control values for Power Control from

the master. The power control procedures are defined by the master and the

parameters are sent to the slaves.

If the WEB`log is operated as a slave, control values which are used in the event of a

failure in communication with the master must be defined.

The following figures show the possible settings:

Fig. 6: WEB`log definition as slave – general broadcast

Fig. 7: WEB`log definition as slave – group broadcast

Input box Meaning

Master (none) Transfers no control value information to slaves (Fig. 3)

Master (to all slaves) Transfers control value information as a broadcast to all

available slaves (Fig. 4)

Master (slave group) Transfers control value information as a broadcast to all slave

groups (Fig. 5)

Slave (general broadcast

messages)

Receives control value information from the master via general

broadcast (Fig. 6)

Slave (group broadcast

messages)

Receives control value information from the master via group

broadcast (Fig. 7)

Slave group Slave group ID for addressing

The activated master data logger sends information on active and reactive

power values to slaves. Active and reactive power procedures can be set and

configured on the master only.

In most cases, the operating modes Master (to all slaves) and Slave (general

broadcast message) are sufficient.

A number of slave groups are needed if data loggers which belong to the

systems of various grid connection points are used within the same Ethernet

network.


Fallback operation

In slave mode, the “Options” heading contains input boxes in which fixed default

values for the inverters in the event of a failure in communication between the master

and slave can be stipulated. Specifying default values in this way is referred to as

fallback.

Fig. 8: Fallback defaults, example cosφ Fix

Input box Meaning

Active power default

Default value in fallback

mode

Active power level in the event of communication failure in

% of the agreed connection power PAV

Reactive power default

Fallback value It is possible to select a reactive power control procedure in

the event of a communication failure:

cos φ Fix, Q Fix or an inverter internal procedure

None No reactive power default will be sent to the inverters in

fallback mode

cos φ Fix Use of the power factor as a control value in fallback mode

Q Fix Use of the reactive power as a control value in fallback mode

Inverter internal In fallback mode, the reactive power procedure implemented

in the inverter will be used

5.3 Power Control system data

The system data need to be entered at this point. These are basic values for the

majority of the power control procedures.

It is imperative that parameters in this section are entered correctly in order to

ensure the proper function of power control procedures and system control

loop.

Fig. 9: Power control system data

Input box Meaning

Agreed connection power

PAV

Maximum feed-in active power at the grid connection point as

agreed upon with the grid operator

Agreed maximum

apparent power SAmax

Maximum apparent power at the grid connection point as

agreed upon with the grid operator

Nominal voltage AC UNom Nominal voltage at the grid connection point


5.4 Power control procedures for the meteocontrol Power Control

The WEB’log PRO Unlimited is able to use a whole range of different procedures for

controlling the power of your PV system. However, an additional PCU, PCU+ and/or a

power quality analyser must be used for the more extensive procedures.

The active and reactive power procedures selected determine the processing type of

the requirements received.

Various procedures with different control values are brought together under

these active and reactive power procedures. Select the relevant procedure

according to the requirements.

The various procedures cannot use any control value sources or be combined at will.

A procedure for active power reduction can be selected without adding a procedure

for reactive power control. (Selecting the procedure for reactive power control is

optional).

A procedure for reactive power control can only be selected if a procedure for active

power reduction was chosen (selecting the procedure for active power reduction is

required).

An individual input screen for selecting parameters for the particular procedures

selected is displayed.

Normal operation

In normal operation,

control values are determined and sent to the inverters,

changes to the requirements are logged and

a notification is sent when changing the active power reduction (if notification is

configured) from the requirements in accordance with the defined rules.

Fallback operation

In the event of a communication failure between PCU and WEB`log or master and

slave WEB‘log, i.e. if no default values are received at that time, fallback operation

becomes active after a delay period of 10 minutes. In this case, the pre-configured

default values will be used during fallback. During the delay period, the parameter set

of the last valid control values is used.

If Power Control is enabled with the set of required information being incomplete,

fallback operation will likewise be enabled immediately.

Possible causes:

Error when receiving the requirements (digital-in or analogue-in).

Error in the definition of the configuration for the power procedures chosen.

Communication error between PCU and WEB`log master


Setting up the power control procedures

Fig. 10: Active power and reactive power procedures

Input box Meaning

Active power default

Active power procedure Active power procedure selection

Capping at PAV When this option is selected, the data logger ensures the

agreed connection power PAV is not exceeded.

Default value in fallback

mode

Default value for active power in fallback mode

Reactive power default

Procedure switching Enables switching between various reactive power

procedures via the digital inputs

Reactive power procedure Reactive power procedure selection

Q procedure

gradient limitation

Enables gradient limitation

The maximum permitted reactive power change per second

can be specified

cos φ (Fix) default value in

fallback mode

Default value for power factor in fallback mode

Q (Fix) default value in

fallback mode

Default value for reactive power in fallback mode

Configuration Brings up the configuration settings for the selected active

and reactive power procedure

A description of all power control procedures and the relevant settings can be

found in Chapters 5.5 and 5.6.


System control loop

The system control procedure ensures that inconsistencies in the power fed-in,

caused by the transmission route between the inverter and grid connection point

(GCP), are compensated (low voltage or medium voltage). As a result, the

requirements imposed by the grid operator are met at the GCP itself.

The GCP controlling procedure is only active if the reactive power procedure is

selected.

For correct functionality of the system control loop, the following parameters must be

entered correctly.

Agreed connection power PAV [kW]

Agreed maximum apparent power SAmax [kVA]

Nominal voltage AC UNom [kV]

Parameter model [transformer / no transformer] *

Transformer nominal power [kVA] *

Lower Plimit [%]

Lower cosφlimit *

Upper Qlimit [%] *

The "Upper Qlimit" field automatically generates its contents from the "Lower

cosφlimit" field and vice versa.

Therefore it is sufficient to enter the data provided by the inverter manufacturer

in one of the two fields. Once the cursor leaves the field or if the enter key is

pressed, the relevant other field is updated as well.

The following data also has to be entered under Configuration > System Data:

Installed power [kW] *

ATTENTION

- All data must be entered correctly. The parameters marked with * are

particularly important when it comes to ensuring correct control.

- Incorrectly entered data or values outside the technically feasible range of

the inverter(s) will result in control malfunctions.


Fig. 11: GCP control loop configuration

Input box Meaning

System control loop Activates the system control loop

Parameter model Selection of the parameter model to calculate the start

configuration control loop

Transformer nominal

power

Nominal power of the transformer

Lower Plimit Work threshold of the NAP control loop

Lower cos φlimit Work threshold of the NAP control loop

Upper Qlimit Work threshold of the NAP control loop

Generate start

configuration

Generate the start configuration for the GCP control loop

A power quality analyser at the grid connection point is essential for the

operation of the system control loop. Information regarding power quality

analysers can be found in Chapter 6.


5.5 Active power procedure

5.5.1 P(DI)

With this procedure, the active power P is used as the control value.

The default value is provided by the grid operator as a digital input signal. This is

possible for example via a ripple control receiver connected to the digital inputs of the

PCU. The reduction levels are assigned to the digital inputs via a parameter table. In

this case, every digital PCU input corresponds to a default value.

Feedback regarding reduction is provided via the digital outputs of the PCU.

Only individual outputs of the ripple control receiver may be assigned. Bit

samples (e.g. DI 1,2,4 = Adr. 007 for assigning the default value) are not

permitted.

In contrast, the P(DI) internal procedure allows bit samples.

Fig. 12: Active power procedure – P(DI) control

Input box Meaning

Number Control number

Active Setting whether the rule should be applied

Input Number of the IO port

Output Number of the IO port

P% Relative active power in percent (in relation to PAV)


5.5.2 P(AI)


The default value is provided by the grid operator as an analogue input signal. This is

possible for example via a remote control system with analogue outputs connected to

the analogue input (4–20 mA current signal in accordance with DIN IEC 60381-1) of the

PCU. Feedback is provided via the analogue output (4-20 mA current signal in

accordance with DIN IEC 60381-1).

The power reduction from the analogue value is calculated via a linear equation. For

the configuration, the value pairs P1 and P2 are required, which are at the end of the

line (min and max).

Fig. 13: Active power procedure – P(AI) control

Input box Meaning

AI Number of the analogue input

The lowest measured

value

Value pair for defining the lowest operating point (example: 4

mA corresponds to zero percent)

The highest measured

value

Value pair for defining the highest operating point (example: 20

mA corresponds to one hundred percent)

Sensitivity Point from when a change in the analogue input results in a

change in the control value (given in %)


5.5.3 P Fix

With this procedure, a fixed active power limit is used as the control value. To this end,

a configurable, consistent value is saved. With this procedure, a downward inverter

regulation to 70% or 60% for example is possible.

A PCU is not required for this procedure.

Feedback on the set power level is not possible with this procedure.

5.5.4 P(DI) internal


The default value is provided by the grid operator as a digital input signal. This is

possible for example via a ripple control receiver connected to the internal digital

inputs of the WEB`log.

Unlike with the P(DI) procedure with PCU, the use of bitmasks is permitted for the

P(DI) internal procedure.

The digital inputs are assigned to the reduction levels via a parameter table. In this

case, every digital PCU input corresponds to a requirement value.

The PCU is not required for this procedure.

Feedback on the set power level to the grid operator is not possible with this

procedure.

Fig. 14: Active power procedure – P(DI) internal

Input box Meaning

Digital inputs column

(DI 4 - DI 1)

Configurable for up to 16 different power levels. Green

indicates what input must be activated

Specification Power requirement in percent when occupying the relevant

digital inputs


5.6 Reactive power procedure

5.6.1 Cosφ (DI)

With this procedure, the power factor cosϕ is used as the control value. The default

value is provided by the grid operator as a digital input signal. This is possible for

example via a remote control system with digital outputs connected to the digital

inputs of the PCU.

Feedback is then provided via the digital outputs of the PCU.

The assignment is carried out via a parameter table. The breakdown and assignment of

the levels are freely selectable. In doing so, every digital PCU input corresponds to a

requirement value.

Fig. 15: Reactive power procedure – cosφ (DI)

Input box Meaning





cos φ / excitation Power factor control values for reactive power reduction


5.6.2 Cosφ (AI)

With this procedure, the power factor cos ϕ is used as the control value. The default

value is provided by the grid operator as an analogue input signal. This is possible for

example via a remote control system with analogue outputs connected to the

analogue input of the PCU.

Feedback can be provided via the analogue output of the PCU.

The value is provided by the grid operator as an analogue input signal (4 – 20mA).

The power factor is calculated from the analogue value via a linear equation. For the

configuration, the value pairs P1 and P2 are required, which are at the end of the line.

Furthermore, the excitation type per point is required.

Fig. 16: Example cosφ (AI) characteristic curve

Fig. 17: Reactive power procedure – cosφ (AI) control

Input box Meaning


The lowest measured

value

Indicated in mA and %. Value pair for defining the lowest

operating point (example: 4mA corresponds to factor 0.95 –

overexcited)

Highest measurement

value

Indicated in mA and %. Value pair for defining the highest

operating point (example: 20mA corresponds to factor 0.95 –

under- excitated)

Sensitivity Sensitivity setting: indicates from when a change to the

analogue input results in a change to the control value


5.6.3 Cosφ Fix

With this procedure, a fixed power factor cosϕ is used as the control value. To this

end, a configurable, consistent value is saved. No feedback is provided.



5.6.4 Cosφ (P)

With this procedure, the power factor cosφ is used as the control value. By changing

the power factor, it is possible to influence the power fed-in at the grid connection

point. Here the selected measuring device records the active power (P) fed-in at the

grid connection point and transfers it to the data logger, which then assigns the cosφ

control value to the relevant power on the basis of a 4 point characteristic curve.

The following details are required for the configuration:

The 4 characteristic points P1 to P4 of the characteristic curve

Details of the areas in which the points lie (overexcited or under- excitated)

Fig. 18: Reactive power procedure – cosφ (P) control

Input box Meaning

Curve Type of curve

Point 1…4 Support points 1…4

PHyst Hysteresis as the ratio of P/PAV



This procedure requires a power quality analyser that has been configured and

connected to the data logger.


5.6.5 Cosφ (U)

With this procedure, the power factor cosϕ is used as the control value. By changing

the power factor, it is possible to influence the voltage at the grid connection point. To

do this, the voltage U at the grid connection point is recorded by the selected

measuring device and transferred to the data logger, which then assigns the cosφ

control value to the relevant voltage on the basis of a linear equation.


The 4 points P1 to P4 of the characteristic curve

Details in what areas the points are (overexcited or under- excitated)

Fig. 19: Reactive power procedure – cosφ (U) control

Input box Meaning

Curve Type of curve


UHyst Hysteresis as the ratio of U/UNom






5.6.6 Q(DI)

With this procedure, the reactive power Q is used as the control value. The default

value is provided by the grid operator as a digital input signal, which is possible for

example via a remote control system with digital outputs connected to the digital

inputs of the PCU.

Feedback is provided via the digital outputs of the PCU.

The assignment is carried out via a parameter table. The breakdown and assignment of

the levels are freely selectable. In doing so, every digital PCU input corresponds to a

requirement value.

Fig. 20: Reactive power procedure – Q(DI) control

Input box Meaning





Q(%) / excitation Reactive power control value for reactive power reduction in

percent


5.6.7 Q(AI)

With this procedure, the reactive power Q is used as the control value.

The default value is provided by the grid operator as an analogue input signal, which is

possible for example via a remote control system with analogue outputs connected to

the analogue input of the PCU.

Feedback is provided via an analogue output of the PCU.

The value is provided by the grid operator as an analogue input signal (typically: 4–

20mA). The reactive power is calculated from the analogue value via a linear equation.


The value pairs P1 and P2, which are at the end of the line (min and max).

Details in what areas the points are (overexcited or under-excitated)

Fig. 21: Q(AI) characteristic curve

Fig. 22: Reactive power procedure – Q(AI) control

Input box Meaning


The lowest measured

value

Indicated in mA and %. Value pair for defining the lowest

operating point (example: 4 mA corresponds to 15 % -

overexcited)

The highest measured

value

Indicated in mA and %. Value pair for defining the highest

operating point (example: 20 mA corresponds to 15% - under-

excitated)

Sensitivity Sensitivity setting: indicates from when a change to the

analogue input results in a change to the control value


5.6.8 Q fix

With this procedure, a fixed reactive power Q is used as the control value. To this end,

a configurable, consistent value is saved in the WEB`log. No feedback is provided.



5.6.9 Q(U)

With this procedure, the reactive power Q is used as the control value. By changing

the reactive power, it is possible to influence the voltage at the grid connection point.

To do this, the voltage U at the grid connection point is recorded by the selected

measuring device and transferred to the data logger, which then assigns the Q control

value to the relevant voltage on the basis of a linear equation.

Power quality analysers are supported as measuring devices.


The 4 points P1 to P4 of the characteristic curve

Details in what areas the points are (overexcited or under- excitated)

Fig. 23: Reactive power procedure – Q(U) control

Input box Meaning

Curve Type of curve


UHyst Hysteresis as the ratio of U/UNom

Lower limit cos φLimit Lower cos φ limit up to which the characteristic curve is

moved, then the selected cos φ is used as the fixed value






5.6.10 Inverter cosφ (P)

This procedure is an inverter-internal procedure. The data logger has no influence over

control and allows the inverters to take over internal control. The power factor cosϕ is

used as the control value.

For the majority of inverters supporting this procedure, no settings need to be

made in the data logger. The parameters should be saved in the inverter itself.

For details of how to do this, please read the operating manual for the particular

inverter.

5.6.11 Inverter Q(U)

This procedure is an inverter internal procedure. The data logger has no influence over

control and allows the inverters to take over internal control. The reactive power Q is

used as the control value.

For the majority of inverters that support this procedure, no settings need to be

made in the data logger. The parameters should be saved in the inverter itself.

For details on the respective steps, please read the operating manual for the

inverter in use.


5.7 Enabling Power Control

Once all settings for meteocontrol Power Control have been made, Power Control

must be enabled. It is recommended to start Power Control only after the

configuration has been completed.

Fig. 24: Enabling Power Control

Input box Meaning

Power Control Enables or disables the PC

Save Saves the settings

5.8 Power Control status

Under Online Values > Power Control, you can bring up the current Power Control status.

Fig. 25: Power Control online values

Description Meaning

Operating status Current Power Control status

Active power procedure Displays the current active power procedure

Reactive power procedure Displays the current reactive power procedure

Current control value Control value requirement for active and reactive power

procedures in percent

The highlighted values are updated every 10 seconds. It is not possible to

configure these online values.


5.9 Power Control settings via the data logger display

The Power Control status can be queried and modified via the WEB’log PRO unlimited

display. Configuration of the meteocontrol Power Control on the other hand can only

be done via the web browser, as detailed in the previous chapters.

The WEB'log's user groups are password protected.

The standard passwords are:

User group "End customer" password "0030“

User group "Installer“ password "0020“

User group "Administrator“ password "0010“

Menu structure on the PRO unlimited display

Settings**

PC settings *** PC status enabled Power Control is active disabled Power Control is inactive

* User group “End customer”

** User group “Installer”

*** User group “Administrator”


6. Power quality analyser Because a power quality analyser (PQA) is a technical device with numerous functions,

a user-specific configuration is necessary.

It is recommended to install the transmitters at the grid connection point (support type

current transformer, voltage converter) in accordance with the generator meter arrow

system.

When selecting the components, the precision classes of at least 0.5 (fine

measurement device classes) should be ensured.

Furthermore, power and current converter must be selected in order to utilize the

measurement range of the power quality analyser to its fullest possible extent. To

control the active power, a single-phase measurement is considered sufficient.

However, a three-phase measurement is better recommended, as at the medium

voltage end the transformer usually has a triangular switching group, while the voltage

is measured against a star point.

To allow the use of Power Control, meteocontrol offers a suitable power quality

analyser (UMG604), which enables the measurements needed for a number of

procedures to be taken at the grid connection point.

Electrical installation of the PQA

The electrical planning and installation of PV systems, in particular the connection of

the power quality analyser at the grid connection point, are not covered by this manual.

However, the following steps for the use of the PQA must be observed:

PQA to GCP

The power quality analyser is connected to the grid connection point in accordance

with the relevant low voltage and/or medium voltage directives. Depending on the

system design, transmitters are required (support type current transformer, voltage

converter).

PQA to WEB`log

A power quality analyser (PQA) is always connected to the WEB’log configured as

the master via Modbus-RTU or Modbus-TCP. The device should be connected and

configured in accordance with the “Connecting Modbus devices" section of the

WEB’log operating manual.


7. Grid feed-in management overview

Supported WEB’logs Necessary accessories

Web’log Pro Unlimited

WEB‘log

Light+ 20

WEB‘log

Basic 100

WEB‘log Pro

Unlimited

Power quality

analyser (PQA)

PCU+

Active power procedure

P DI)

WEB`log

internal**

+ + +

P (DI) + +

P (AI) + +

P (fix) + + +

Inverter

internal

Driver-

dependent

Reactive power procedure

cosφ (DI) + +* +

cosφ (AI) + + +

cosφ (fix) + + + +*

cosφ (P) + +

cosφ (U) + +

Q (fix) + + + +*

Q (U) + + +

Inverter

internal

Driver-

dependent

Driver-

dependent

Driver-

dependent

* :

**:

PQA not necessary for systems connected to the low-voltage grid; PQA not

compatible with the Web’log Basic 100 and the Light+ 20

Connection of ripple control receiver to the internal digital inputs of the

WEB'log. For other procedures, connection is via the PCU.


8. List of figures Fig. 1: PCU<->Power Control functionality ................................................................... 8

Fig. 2: Power Control functionality ................................................................................ 9

Fig. 3: WEB`log master with broadcast to all slaves .................................................... 11

Fig. 4: WEB`log master without slaves ....................................................................... 11

Fig. 5: WEB`log master with slave groups .................................................................. 11

Fig. 6: WEB`log definition as slave – general broadcast .............................................. 12

Fig. 7: WEB`log definition as slave – group broadcast ................................................. 12

Fig. 8: Fallback defaults, example cosφ Fix ................................................................. 13

Fig. 9: Power control system data .............................................................................. 13

Fig. 10: Active power and reactive power procedures ................................................ 15

Fig. 11: GCP control loop configuration ....................................................................... 17

Fig. 12: Active power procedure – P(DI) control .......................................................... 18

Fig. 13: Active power procedure – P(AI) control .......................................................... 19

Fig. 14: Active power procedure – P(DI) internal ......................................................... 20

Fig. 15: Reactive power procedure – cosφ (DI) ............................................................ 21

Fig. 16: Example cosφ (AI) characteristic curve ........................................................... 22

Fig. 17: Reactive power procedure – cosφ (AI) control ................................................ 22

Fig. 18: Reactive power procedure – cosφ (P) control ................................................. 23

Fig. 19: Reactive power procedure – cosφ (U) control ................................................. 24

Fig. 20: Reactive power procedure – Q(DI) control ...................................................... 25

Fig. 21: Q(AI) characteristic curve ............................................................................... 26

Fig. 22: Reactive power procedure – Q(AI) control ...................................................... 26

Fig. 23: Reactive power procedure – Q(U) control....................................................... 27

Fig. 24: Enabling Power Control .................................................................................. 29

Fig. 25: Power Control online values ........................................................................... 29

Spicherer Str. 48 D-86157 Augsburg Phone +49 (0) 821 / 3 46 66-88 Fax +49 (0) 821 / 3 46 66-11 [email protected] www.meteocontrol.de

Text and illustrations represent state-of-the-art technology at the time of printing May be subject to technical

updates We assume no liability for printing errors.

Version 20131213

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