JP5738098B2 - Gas turbine system - Google Patents

Description

  The present invention relates to a gas turbine system, and more particularly, to a gas turbine system that uses a thyristor to make a generator a starting motor.

  2. Description of the Related Art Conventionally, there is known a gas turbine system that uses a coaxial generator as an electric motor to assist the startup of the gas turbine when the gas turbine is started up and accelerated. In such a gas turbine system, electric power is supplied to the generator through a thyristor starting device using a thyristor (see, for example, Patent Document 1).

  FIG. 4 shows a system diagram of a gas turbine system provided with a conventional thyristor starting device. As shown in FIG. 4, the gas turbine system 110 supplies power to the gas turbine 1, the gas turbine control device 2 that controls the gas turbine 1, the generator 14 that is driven by the gas turbine 1, and the generator 14. And a thyristor starting device 104 to be controlled.

  When starting the gas turbine 1, the thyristor control unit 105 constituting the thyristor starter 104 controls the output torque of the generator 14 according to the time since the start of the gas turbine 1. The thyristor control unit 105 outputs a torque signal corresponding to the time from the start of the gas turbine to the generator 14 according to a predetermined relational expression.

  The predetermined relational expression can be represented by a graph as shown in FIG. 5, for example. As shown in FIG. 5, the relational expression is composed of four function contacts. From the start of the gas turbine 1 to a predetermined time, the time and output are linearly increased so as to increase the output torque of the generator 14 linearly. Torque is related. Then, after the time when the sufficient increase in the gas turbine speed is estimated, the output torque is set to a constant value, and then the output torque is gradually decreased toward the time when the gas turbine is estimated to reach the self-sustaining rotation. In this way, time and output torque are related.

Japanese Patent No. 3105673

  By the way, in the conventional gas turbine system 110 as described above, the thyristor controller 105 controls the output torque of the generator 14 in accordance with the time from the start of the gas turbine 1. That is, although the rotational speed of the gas turbine 1 is taken into account, strictly speaking, the generator 14 is not controlled according to the rotational speed, and the generator 14 is empirically determined according to the time elapsed since the start of the gas turbine. It only changes the output torque.

  As described above, when the control is dependent only on the time from the start-up, when the gas turbine 1 does not reach the rotation speed assumed at that time due to a lack of fuel energy or a decrease in the atmospheric temperature. The output torque of the generator 14 is insufficient, which may cause combustion vibration. On the other hand, if the gas turbine 1 has a higher rotation speed than the assumed rotation speed, the generator 14 will help start more than necessary, and this will also lead to vibration of the gas turbine 1. There's a problem.

  Further, in a blast furnace gas-fired gas turbine that is installed in a steel plant and uses blast furnace gas generated in the production process of the steel plant as a fuel, parameters such as calorie of the fuel gas greatly vary depending on the operating condition of the blast furnace. In order to cope with this parameter variation, the relational expression is usually adjusted by repeating the trial operation of the gas turbine, and the final relational expression is constructed.

  However, the above-described conventional gas turbine system 110 has few function contacts for associating the time since start-up with the output torque of the generator 14, and it is possible to create a relational expression corresponding to fluctuations in the calories and atmospheric conditions. It was difficult. That is, there are few adjustment margins for the relational expression, and in some cases, the gas turbine may not be started. There were also problems such as an increased risk of combustion vibration during the test run and a longer test run period.

The present invention employs the following means in order to solve the above problems.
The present invention is a gas turbine system including a thyristor starter that controls an output torque when a generator of a gas turbine is used as an electric motor by a thyristor control unit switching the thyristor, and the rotational speed of the gas turbine And a torque signal calculation unit that outputs a torque signal of the generator corresponding to the rotation number output from the rotation number detection unit, wherein the thyristor control unit is based on the torque signal. The thyristor is switched, and the torque signal calculation unit calculates using a relational expression of the torque signal of the generator corresponding to the rotational speed of the gas turbine, and the relational expression is a curve having a peak, The curve up to the peak is formed by a plurality of contacts .

  According to the said structure, it was set as the structure which a torque signal calculating part outputs a torque signal to a thyristor control part based on the rotation speed of a gas turbine. As a result, the generator used as the electric motor is controlled so as to generate an output torque corresponding to the rotational speed of the gas turbine, so that stable control is possible even when the rotational speed of the gas turbine fluctuates due to external conditions. It becomes possible.

  In addition, since the relational expression for calculating the torque signal based on the rotational speed can be adjusted more flexibly, even if the external conditions that affect the start of the gas turbine fluctuate, the relation corresponding to this fluctuation range An expression can be constructed.

  Further, the torque signal calculation unit calculates using the relational expression of the torque signal of the generator corresponding to the rotational speed of the gas turbine, the relational expression is a curve having a peak, and the curve after the peak is It is preferably formed by a plurality of contacts.

  Furthermore, it is preferable to control the output torque of the generator from the start of the gas turbine to the self-sustaining rotation through ignition.

  According to the above configuration, the rotation speed of the gas turbine is monitored until the gas turbine is rotated independently, and the output torque of the generator is controlled according to the rotation speed, so that the gas turbine can be started more stably. can do.

  According to the present invention, the torque signal calculation unit outputs the torque signal to the thyristor control unit based on the rotational speed of the gas turbine. As a result, the generator used as the electric motor is controlled so as to generate an output torque corresponding to the rotational speed of the gas turbine, so that stable control is possible even when the rotational speed of the gas turbine fluctuates due to external conditions. It becomes possible.

It is a systematic diagram of the gas turbine system concerning this embodiment. It is an electrical circuit diagram of the thyristor starting device according to the present embodiment. It is a graph which shows the relational expression which the torque signal calculating part which concerns on this embodiment uses for the calculation of the output torque of a generator. It is a systematic diagram of the conventional gas turbine system. It is a graph which shows the change of the output torque of the generator from the conventional gas turbine starting.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a system diagram of a gas turbine system 10 of the present embodiment.
As shown in FIG. 1, the gas turbine system 10 receives a gas turbine 1, a gas turbine control device 2 that controls the gas turbine 1, and a rotation speed signal of the gas turbine 1 that is output from the gas turbine control device 2. And a thyristor starter 4 that controls the generator 14 of the gas turbine 1 based on the torque signal output from the torque signal calculation unit 3.

  The gas turbine 1 includes a compressor 11 that sucks combustion air into compressed air, and a combustor that generates high-temperature combustion gas by injecting fuel into the compressed air sent from the compressor 11 and burning it. 12 and a turbine 13 that is located downstream of the combustor 12 and is driven by the combustion gas exiting the combustor 12. In the gas turbine system 10, the compressor 11, the turbine 13, and the generator 14 are connected to each other by a coaxial, and the turbine 13 drives the generator 14.

  The generator 14 is configured to be used as a starting motor for the gas turbine 1. In other words, when the gas turbine 1 is started, the generator 14 is used as an electric motor, and the gas turbine 1 is configured to be a power source for faster stabilization.

  The gas turbine 1 is controlled by a gas turbine control device 2. The gas turbine control device 2 is a device that adjusts the fuel flow rate based on the input of each sensor (not shown), and includes a rotation speed detection unit 17 having a rotation speed detection function for detecting the rotation speed of the gas turbine 1. The rotational speed signal of the gas turbine 1 output from the rotational speed detection unit 17 is input to the torque signal calculation unit 3. Details of the torque signal calculation unit 3 will be described later.

  The thyristor starter 4 is a device that enables the generator 14 to be used as an electric motor by a semiconductor dry rectifier using a thyristor (silicon controlled commutator). The thyristor starter 4 changes the armature applied voltage using the thyristor and uses the generator 14 as an electric motor. The thyristor starter 4 includes a thyristor 16 (see FIG. 2) and a thyristor control unit 5 that controls the thyristor 16.

FIG. 2 is an electric circuit diagram of the thyristor starting device 4. As shown in FIG. 2, the thyristor starter 4 is a device that rectifies a three-phase AC power supply by a thyristor 16 and supplies the rectifier to an armature 18 via a brush 17.
The thyristor 16 is switching-controlled by the thyristor controller 5. The thyristor control unit 5 is a part that gate-controls the thyristor 16 by the ignition phase control. The thyristor 16 is controlled in its conduction start angle by the thyristor control unit 5, the armature applied voltage is adjusted, and the generator rotation The number is controlled. Since the thyristor 16 conducts current only in one direction, usually two sets of thyristors are in a bridge configuration as shown in FIG.

The torque signal calculation unit 3 is an analog interface that outputs a torque signal of the generator 14 to the thyristor starter 4 based on the input rotation speed signal of the gas turbine 1.
The torque signal of the generator 14 is calculated based on the rotational speed signal of the gas turbine 1 using the relational expression shown in FIG. The relational expression is a torque curve with the rotational speed as the horizontal axis and the output torque as the vertical axis.

  The zero point on the horizontal axis coincides with the start timing of the gas turbine 1. In addition, at the time of start-up, the gas turbine 1 performs an initial rotation (turning) for preventing deflection. That is, the activation of the gas turbine 1 is not the activation from the rotation speed 0 but the activation from the low-speed rotation. The control by the thyristor control device 4 is performed until the gas turbine 1 enters a self-sustaining rotation. When the gas turbine 1 enters self-sustained rotation, the control of the generator 14 by the thyristor starter 4 ends.

  The torque curve is composed of a function contact consisting of a set of 10 rotational speeds and output torque. Until the predetermined rotational speed is reached, the rotational speed and output torque are set so that the output torque rises substantially linearly. Is associated. Further, after reaching the predetermined rotational speed, the rotational speed and the output torque are associated with each other so as to linearly decrease the output torque.

  That is, the torque signal calculation unit 3 controls the generator 14 so that the generator 14 (electric motor) outputs a torque proportional to the rotation speed when the rotation speed of the gas turbine 1 is equal to or lower than the predetermined rotation speed. As the rotation increases, the gas turbine 1 is ignited, and the rotation speed of the gas turbine 1 approaches the rotation speed at which self-sustaining rotation is possible. Next, since the assist by the generator 14 is not necessary at a predetermined rotational speed or higher, control is performed so that the torque is reduced as the rotational speed increases.

  Further, as described above, the torque curve is constituted by 10 function contacts having one peak. These function contacts can be adjusted as appropriate according to the solid difference of the gas turbine 1. Specifically, adjustment is performed so that normal rotation and rise can be performed even when there is a change in the state of the fuel or the state of the atmosphere after a trial run. For example, as shown in FIG. 3, the torque curve of the relational expression of the present embodiment has a slightly convex curve that reaches the peak. This is a result of adjusting the functional contacts constituting the torque curve in the vertical direction through a trial run.

  Further, the larger the number of function contacts in the torque curve, the better. However, the number of points according to hardware restrictions is appropriately selected. As described above, in order to construct a relational expression that can flexibly cope with external conditions, it is preferable that the curve up to the peak is formed by a plurality of contacts. Further, the curve after the peak is preferably formed by a plurality of contacts.

  The torque signal of the output torque determined in the process as described above is output from the torque signal calculation unit 3 and input to the thyristor control unit 5 of the thyristor starter 4. The thyristor control unit 5 controls the generator 14 by switching the thyristor 16 based on this torque signal, and the generator 14 outputs an output torque corresponding to the rotational speed of the gas turbine 1.

  According to the embodiment, the torque signal calculation unit 3 is configured to output a torque signal to the thyristor control unit 5 based on the rotational speed of the gas turbine 1. Thereby, since the generator used as the electric motor 14 is controlled so as to generate an output torque corresponding to the rotational speed of the gas turbine 1, even when the rotational speed of the gas turbine 1 fluctuates due to external conditions, it is stable. Control becomes possible.

  Further, since the relational expression for calculating the torque signal based on the rotational speed is composed of 10 function contacts, the relational expression can be adjusted more flexibly. As a result, even when the external condition that affects the start-up of the gas turbine 1 changes, it is possible to construct a relational expression corresponding to this fluctuation range. Furthermore, by expanding the adjustment margin, it is possible to reduce risks such as combustion vibrations during the trial run, and to shorten the trial run period.

  Further, since the rotation speed of the gas turbine 1 is monitored until the gas turbine 1 reaches the self-sustaining rotation, and the output torque of the generator 14 is controlled according to the rotation speed, the gas turbine 1 can be started more stably. can do.

  Furthermore, by adding the torque signal calculation unit 3 as an analog interface, the thyristor starter 4 can be applied to an existing gas turbine system, so that the thyristor starter 4 can be operated without significant changes. Can be made.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the embodiment described above, the torque signal calculation unit 3 is configured to calculate the output torque from the rotational speed of the gas turbine 1 output from the gas turbine control device 2. It is good also as a structure where the torque signal calculating part 3 refers the rotation speed of the gas turbine 1 uniquely without going through.

DESCRIPTION OF SYMBOLS 1 ... Gas turbine, 2 ... Gas turbine control apparatus, 3 ... Torque signal calculating part, 4 ... Thyristor starting device, 5 ... Thyristor control part, 10 ... Gas turbine system, 14 ... Generator, 15 ... Speed detection part

Claims (4)

A gas turbine system comprising a thyristor starter that controls an output torque when a generator of a gas turbine is used as an electric motor by switching a thyristor by a thyristor control unit,
A rotational speed detector for detecting the rotational speed of the gas turbine;
A torque signal calculation unit that outputs a torque signal of the generator corresponding to the rotation number output from the rotation number detection unit;
The thyristor control unit switches the thyristor based on the torque signal ,
The torque signal calculation unit calculates using a relational expression of the torque signal of the generator corresponding to the rotation speed of the gas turbine,
The relational expression is a curve having a peak, and the curve up to the peak is formed by a plurality of contact points . The gas turbine system according to claim 1, wherein the curve after the peak is formed by a plurality of contact points. A gas turbine system comprising a thyristor starter that controls an output torque when a generator of a gas turbine is used as an electric motor by switching a thyristor by a thyristor control unit,
A rotational speed detector for detecting the rotational speed of the gas turbine;
A torque signal calculation unit that outputs a torque signal of the generator corresponding to the rotation number output from the rotation number detection unit;
The thyristor control unit switches the thyristor based on the torque signal ,
The torque signal calculation unit calculates using a relational expression of the torque signal of the generator corresponding to the rotation speed of the gas turbine,
The relational expression is a curve having a peak, and the curve after the peak is formed by a plurality of contact points .   The gas turbine system according to any one of claims 1 to 3, wherein an output torque of the generator is controlled from the start of the gas turbine to the self-sustaining rotation through ignition. .

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