= DV938EAC Automatic Load Shed =


EAC DV938 device was designed to satisfy  ENEL and  TERNA’s requirements for automatic load shedding program in power system distribution. The device realize the under frequency load shedding function (UFLS) and under voltage load shedding function (UVLS). DV938  is a last generation digital device  powered by RTEMS Real Time operating system.

Device is equipped with two serial interfaces, one in front and one on the back, either RS232 or RS485 (factory customer selectable), an ethernet 10/100BASE-TX frontal interface and an ethernet optical 100BASE-FX back interface with SC connector. Different options are also available such as a second 10/100BASE-TX back interface, optical interface with ST connector, etc..

An easy to use human-machine interface allows operator to connect directly to DV938; immediate information about device status are given through LED.

DV938 has four  analog input voltage channels software configurable. Remote signalizing is made possible by 15 digital output relays and 4 current loop transmitter (4÷20mA, ±5mA).

Inside DV938 you find

 * 4 minimum/maximum voltage protection threshold (ANSI 27/59);
 * 4 minimum/maximum rate voltage threshold (ANSI 27R/59R);
 * 4 minimum/maximum frequency protection threshold (ANSI 81);
 * 4 minimum/maximum rate frequency protection threshold (ANSI 81R).  

DV938 works in two ways: the first one uses only one analog voltage input (operating mode M1), the second one uses three voltage inputs selected from two different group of three phase voltage (operating mode M2). The group can be selected from digital input state.

To prevent  incorrect trip, three kinds of  stop protections are available:

 * Minimum/Maximum voltage (ANSI 27/59);
 * Maximum delta frequency between phases;
 * Maximum delta voltage between phases. 

Field connection is achieved through two 50 poles rectangular connectors.

DV938 is supplied of two software programs: the first one allowing parametrization and field monitoring, the second one to analyze fault  recording (voltage, rate-voltage, frequency, rate-frequency, etc.) of each trip.

DV938EAC is installed in italian substations and work to satisfy TERNA load shedding program.
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'''Technical data:'''

 [wiki:TBR/UserApp/Automatic_Load_Shed Automatic Load Shed] 


'''View the product brochure:'''

 [English: http://www.logiclab.it/Documents/BrochureEAC_ENG.pdf]
 [Italian: http://www.logiclab.it/Documents/BrochureEAC.pdf]


'''Website:'''

 [LogicLab: http://www.logiclab.it]
 [DV938EAC(english site): http://www.logiclab.it/en/DV938.htm]
 [DV938EAC(italian site): http://www.logiclab.it/it/DV938.htm]


'''RTEMS LogicLab page:'''

[wiki:TBR/UserApp/LogicLab_S.r.l. LogicLab S.r.l.]


'''Other LogicLab Applications

 ''PowerProbe - Digital Fault Recorder''
 :Description: [wiki:TBR/UserApp/PowerProbe PowerProbe]
 :Technical data: [[Digital Fault Recorder]]