How to calculate the real value of the metered measurands

acharki

Hello all,

I don't know how to calculate the real value of the metered measurands (WpForward,WqForward,WpReverse,WqReverse); because the values of those measurands in the SIPROTEC doesn't correspond to the values that I have in my S7300 PLC, so I think that there is a mathematical relation between those two values and also the metered measurands is derived from measured values.

So how can I calculate these values to have the same in the SIPROTEC?

Thank you for helping me

ACHARKI

Hello ACharki;

Here is the Metered Measurands scaling details frrm the 7SJ61 mapping manual (see the attachment). I am assuming that this scaling is the same for all Siprotec relays, since you provide no information on the model you are using.

Metered Measurands are calculated in the relay based on the parameters you provide through DIGSI and require an external pulse generator that operates at a required frequency. See the information for your specific relays for more information.

Please make sure that the required values (Vnom and Inom) are parametrized correctly in your relay, and that the external pulse generator is selected and hooked-up properly.

Once you have set all the parameters, then the conversion factor for display on the PLC/HMI is shown on the attachment.

Hope this helps,

Daniel Chartier

Hello boys,

I´m newer in the forum, actually I need to integrate a SIPROTEC 7sj62 with PLC S7 317. I understand you have developed an integration between those devices. Could you give me some ideas about how to develop the integration, please? I know that the SIPROTEC has a frontal serial port (RS232), is it possible to doing the integration by that serial port? or I need to buy a DP card or any other card to the SIPROTEC ?. I don´t know how to identify the firmware version of the SIPROTEC and how to actualize, help me please. Thanks.

Hello fredy;

The front RS-232 port of the Siprotec relays is only for DIGSI software connection, to parametrize the relay. You will need that software to set ithe relay up, configure the communication board you will eventually install (in the back of the relay), connect internally the digital input/output signals to relay functions...

First you will need to determine what communication protocol you will use, and connect to your PLC: Profibus-DP, Modbus RTU, IEC 61850... Then you will need to check how your PLC can be setup for this communication protocol (most S7 PLCs can be natively Profibus-DP masters, but for Modbus and other protocols you might need to purchase hardware/softwarem supplements).

Once that is achieved, you need to look at the communicationsfiles provided for each relay type: each porotocol has different setups that must be studied and understood before the link will work.

Here is the link to the Siprotec family of relays:

http://w3.siemens.com/smartgrid/global/en/products-systems-solutions/protection/pages/overview.aspx

Here is the link to documentation for the (Siprotec 4) 7SJ62 (open the Downlaods tab, then the Communication Protocols link):

http://w3.siemens.com/smartgrid/global/en/products-systems-solutions/Protection/overcurrent-feeder-protection/Pages/7SJ62.aspx

So, start by selecting the protocol you need, we will be able to help you further when the initial steps are done. Or search the forum for threads on the Siprotec protocols (try "7SJ62 Profibus-DP" in the search box at the right, for example).

Finally, this link will take you to the DIGSI 4 webpage (open the Downloads tab, click on the manuals link, look especially at the Siprotec 4 and DIGSI 4 system manuals):

http://w3.siemens.com/smartgrid/global/en/products-systems-solutions/protection/engineering-evaluation-diagnostic-software/pages/digsi-4.aspx

Hope this helps,

Daniel Chartier