Power plants – Combustion products used as motive fluid – With safety device
Reexamination Certificate
2002-04-09
2004-08-31
Casaregola, Louis J. (Department: 3746)
Power plants
Combustion products used as motive fluid
With safety device
C060S803000
Reexamination Certificate
active
06782691
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a gas turbine plant. Especially, the present invention relates to a gas turbine plant with a monitoring unit to monitor temperature in a turbine outlet and to detect an extraordinary state of the gas turbine plant.
2. Description of the Related Art
FIG. 1
shows an example of a conventional gas turbine plant. The gas turbine plant shown in
FIG. 7
is comprised of a compressor
101
, a gas turbine section
102
, a combustion section
103
and a power generator
104
. External air is taken in by the compressor
101
, and is compressed, and supplied to the combustion section as compression air
105
. Fuel
106
is supplied to the combustion section
103
. The combustion section
103
combusts the fuel
106
using the compression air
105
to form the combustion air
110
. The combustion air
110
is discharged from an exhaust section
112
as exhaust gas
111
after driving the turbine section
102
.
N temperature detectors (N is a positive integer)
113
are provided in the exhaust section
112
in the neighborhood of an outlet of the gas turbine section
102
. The N temperature detectors
113
are on N positions of the circumference of the exhaust section
112
in a constant interval. The N temperature detectors
113
monitor and measure the temperatures T
1
to T
n
on N positions in the neighborhood of the turbine outlet of the gas turbine section
102
, i.e., blade path temperatures. The measured temperatures T
1
to T
n
are supplied to a monitoring unit
115
. The monitoring unit
115
compares each of the temperatures T
1
to T
n
and a predetermined target value. The monitoring unit
115
detects an extraordinary state of the gas turbine plant when the difference of each of the temperatures T
1
to T
n
and a predetermined target value is equal to or larger than a tolerable level and emits a warning signal.
However, the temperatures T
1
to T
n
in the neighborhood of the turbine outlet change even when the gas turbine plant is operating normally. When the output of the gas turbine plant changes, swirler phenomenon is caused. As a result, the combustion gas
110
outputted from the combustion section
103
passes through the turbine section
102
in a twisted state. When the combustion gas
110
is twisted, the blade path temperatures T
1
to T
n
change. Such changes of the blade path temperatures T
1
to T
n
are not caused due to the extraordinary state of the combustion section
103
.
Therefore, it is not possible to improve a detection sensitivity of the extraordinary state of the combustion section
103
by decreasing the tolerable level of the difference between each of the temperatures T
1
to T
n
and the predetermined target value, if the changes of the blade path temperatures T
1
to T
n
are considered.
In conjunction with the above description, a steam monitoring system in a steam cooled type gas turbine is disclosed in Japanese Laid Open Patent Application (JP-P2000-18050A). In this reference, cooling steam is supplied to a cooling object such as a combusting unit and winds. A temperature detector detects an exit temperature of the cooling steam after the cooling. A control apparatus inputs a detection signal from the temperature detector, and compares the detection signal with a predetermined signal. Also, the control apparatus generates a warning signal, a signal for adjusting an opening degree of a fuel flow rate adjusting valve or closing a closing valve, when the detection signal exceeds a predetermined signal.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide a gas turbine plant which monitors blade path temperatures to detect an extraordinary state of a combustion section more correctly.
Another object of the present invention is to provide a gas turbine plant which has a high detection sensitivity of an extraordinary state of a combustion section, even if the changes of the blade path temperatures are caused.
In an aspect of the present invention, a gas turbine plant includes a combustion section, a turbine section, an exhaust section, a temperature detecting unit, and a monitoring unit. The combustion section combusts fuel using air to generate combustion gas. The turbine section is driven with the combustion gas from the combustion section. The exhaust section is connected to the turbine section to exhaust the combustion gas from the turbine section. The temperature detecting unit is provided in the exhaust section to measure a temperature of the combustion gas. The monitoring unit generates a warning signal based on a tolerable level and data corresponding to a temporal change of the temperature measured by the temperature detecting unit to indicate an extraordinary state of the gas turbine plant.
The monitoring unit may include a temperature change determining section which compares the tolerable level and the data corresponding to the temporal change of the measured temperature and generates the warning signal based on the comparison result. In this case, the temperature change determining section may include a delay unit and a difference calculating unit. The delay unit delays the measured temperature by a predetermined time period to produce a delayed temperature. The difference calculating unit calculates a difference between the delayed temperature and the measured temperature and outputs the calculated difference as the data corresponding to the temporal change of the measured temperature.
Also, when the gas turbine plant include a plurality of the temperature detecting units, the monitoring unit may include an averaging circuit and a plurality of temperature change determining sections. The averaging circuit calculates an average temperature of a plurality of the temperatures measured by the plurality of temperature detecting units. Each of the plurality of temperature change determining sections compares the tolerable level and the data corresponding to the temporal change of a temperature difference between the average temperature and a corresponding one of the plurality of measured temperatures and generates the warning signal based on the comparison result. In this case, the temperature change determining section may include a first difference calculating unit, a delay unit and a second difference calculating unit. The first difference calculating unit calculates the temperature difference between the average temperature and the corresponding measured temperature. The delay unit delays the temperature difference by a predetermined time period to produce a delayed temperature difference. The second difference calculating unit calculates a difference between the delayed temperature difference and the temperature difference and outputs the calculated difference as the data corresponding to the temporal change of the temperature difference.
Also, the tolerable level may be determined based on data varying in correspondence to an output of the gas turbine plant. In this case, when the gas turbine plant may include a plurality of the temperature detecting units, the monitoring unit may include an averaging circuit which calculates an average temperature of a plurality of the temperatures measured by the plurality of temperature detecting units, and the data varying in correspondence to an output of the gas turbine plant is the average temperature. Instead, the data varying in correspondence to an output of the gas turbine plant may be a quantity of the fuel supplied to the combustion unit. Otherwise, when the gas turbine plant may include a fuel control valve, the data varying in correspondence to an output of the gas turbine plant may be an opening degree of the fuel control valve.
Also, the monitoring unit further may include a determining unit which compares the measured temperature and a predetermined threshold level and generates another warning signal based on the comparison result.
Also, when the gas turbine plant includes a plurality of the temperature detecting units, the monitoring unit further may include an
Komiyama Hiroya
Nagata Shouichi
Casaregola Louis J.
Mitsubishi Heavy Industries Ltd.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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