GE DGP Series, Instruction Manual

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DGP Digital Generator Protection System GE Power Management
1.4 OTHER FEATURES 1 PRODUCT DESCRIPTION
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Also included are two additional relays (TEST PICKUP and TEST TRIP) that can be configured to operate by a
selected protection function pickup flag and trip output. These two outputs are intended to facilitate testing of
the selected protection function.
A Contact Expansion Unit is also available which can be used with DGP***ACA models. The General Electric
DEC1000 Contact Expansion Unit provides eleven additional output relays that can be factory configured to
user specifications. Refer to the GE Power Management Product Catalog, the GE Power Management Prod-
ucts CD, or instruction book GEK-105561 for additional details on the DEC1000.
1.4.3 START-UP SELF-TESTS
The most comprehensive testing of the DGP is performed during power-up. Since the DGP is not performing
any protection activities at that time, tests (such as RAM tests) that would normally be disruptive to run-time
processing are performed during the start-up. All processors participate in the start-up self-test process. The
processors communicate their results to each other so that any failures found can be reported to the user and
to ensure each processor successfully completes its assigned self-tests before the DGP system begins protec-
tion activity.
During power-up, the microprocessors perform start-up self-tests on their associated hardware (PROM, local
RAM, shared RAM, interrupt controller, timer chip, serial and parallel I/O ports, non-volatile memory, analog
and digital I/O circuitry, MMI hardware, etc.). In addition, the DGP system verifies that the PROM version num-
bers in all processor boards are compatible. The components tested at start-up are listed in Table 6–1: START-
UP SELF-TESTS on page 6–2.
In most cases, if any critical self-test failure is detected, the DGP will not continue its start-up but will not cause
a reset. An attempt will be made to store the system status, to initialize the MMI and remote communications
hardware/software for communication status, and to print a diagnostic message. The critical alarm relay will be
de-energized.
If no failures are detected, the DGP completes initialization of its hardware and software. Next, each processor
board (DAP and SSP) will enable the outputs. As a final step, the DGP checks the results of all the tests to
determine whether to turn the front panel status LED to green.
The start-up procedure takes approximately one minute. As soon as the SSP successfully completes its
PROM test and initializes the display hardware, the message INITIALIZING will be displayed. When the DGP
system initialization is completed, the display is blanked and the relay begins acquiring and processing data.
1.4.4 RUN-TIME SELF-TESTS
Each of the processors has "idle time" when the system is in a quiescent state; that is, when the DGP is not
performing fault or post-fault processing. During this idle time, each processor performs background self-tests
that are non-disruptive to the foreground processing. If any background self-test fails, the test is repeated. To
declare a component FAILED, the test must fail three consecutive times. In the case of critical failures, the
DGP forces a self reset to resume operation again after an intermittent failure. The reset activities are identical
to the start-up activities except that not all start-up self-tests are performed.
A reset is not reported to the user by the DGP system. If the reset is successful, no message is printed, no fail-
ure status is recorded, and the critical alarm is not generated. However, during the reset procedure, the red
LED on the MMI panel will light and a failure code may appear on the MMI display. If the reset is not success-
ful, the processor board will be shut down, leaving the MMI panel displaying the error information. Refer to
Section 6.4: ERROR CODES on page 6–7 for error codes. To prevent continual resets in the case of a solid
failure, both hardware and software will permit only four resets in a one hour period. On the fifth reset, the DGP
will not perform initialization, but will attempt to initialize MMI, communications, and the critical alarm output, as
in the case of a start-up with a critical self-test failure.