Toshiba GR200 Series - 3.4.1 Double command blocking (DCB)

6F2S1914 (0.49)
GRL200 (Soft 033 & 037)
- 562 -
3.4.1 Double command blocking (DCB)
For control functions, the operating principle is that priority is given to the first command
received and shall be executed first. In other words, successive commands received do not have
the right to run until the first command received has failed to complete its operation (that is,
the principle of double command blocking (DCB) is established). The principle is significant for
protection and control devices in the sub-station†. Figure 3.4-1 illustrates how each control
function generates a SLD_RPT signal; the aggregation of SLD_RPT signals is performed in the
CMNCTRL1 function. The resultant signal is output at PLC connection point “DCB SND OR”.
The resultant signal is returned to the respective control function as feedback.
SPOS01 function
Reception of “DCB”
Output of “StSeld”
SPOS02 function
SPOS01_STD_RPT
SPOS03 function
SPOS02_STD_RPT
SPOS03_STD_RPT
SPOS20_STD_RPT
SPOS20 function
DPOS01 function
Reception of “DCB”
Output of “StSeld”
DPOS01_STD_RPT
DPOS72_STD_RPT
DPOS72 function
≥1
CMNCTRL1 function
DCB SND OR
(510001 0008001F42)
To 61850
communication
SPOS function
DPOS function
DPSY function
TPOS function
SOFTSW function
“stVal” message 1
“From 61850
communication
“stVal” message 2
To control functions
in its own
DCB RCV OR
Command “P2-Control” from the remote
510001 0001011001
Figure 3.4-1 DCB operation in CMNCTRL1 function
†Note: Let us assume that the control function in IED-1 controls CB1, as shown in Figure
3.4-2. IEDs -2 to -10 are forbidden to operate their CBs throughout the period that
IED-1 is in operation. Control functions are also forbidden to operate CB1 when
the automatic sequence controlling function (ASEQ) is in operation. We discuss
the ASEQ function later. (See Chapter Control and monitoring application: