JPH0673376U - Load limiting device for power generation turbine - Google Patents

Abstract

(57) [Summary] [Purpose] To obtain a load limiting device for a power generation turbine that does not touch the River Law when the load control is performed in consideration of the River Law when starting the turbine. A hydroelectric power plant comprising a power generation turbine, a turbine generator rotationally driven by the power generation turbine, and a guide vane control device for controlling the opening and closing of a guide vane of the power generation turbine, Immediately after the turbine generator is put in parallel to the power system, the guide vane is taken by a load limiting device that is incorporated in the guide vane control device of the turbine for power generation and limits the opening of the guide vane of the turbine for generating power. It is characterized in that the power flow rate is preset and the discharge rate of the water turbine to the river can be controlled from the minimum flow rate.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to improvement of a load limiting device for a turbine for power generation (hereinafter referred to as a water turbine), and particularly, immediately after a turbine generator (hereinafter referred to as a generator) is inserted in a power system, a discharge rate of a turbine to a river is improved. It relates to a load limiting device for a power generation turbine that can control the flow rate from the minimum flow rate.

[0002]

[Prior art]

 In a reaction type water turbine that is often used as a water turbine, for example, Francis turbine, when starting from a stopped state, it is necessary to give a torque that overcomes the static force. For this reason, a start command is given to the turbine to open the turbine guide vane, and the turbine runner starts to rotate.At the time of starting the turbine, a large amount of water is usually temporarily stored compared to when the turbine is operated with no load. Therefore, the opening of the turbine guide vane at the time of starting the turbine becomes larger than that at the time of no-load operation.

By the way, a guide vane control device for a hydraulic power turbine includes a speed adjusting mechanism that controls the rotational speed of the turbine and a load limiting device that limits the opening of the turbine guide vane. A guide vane opening degree limiting mechanism is provided.

FIG. 3 is a conventional water turbine start control time chart, in which the horizontal axis represents time, and the vertical axis represents the rotational speed of the turbine and the opening of the guide vane. In FIG. 3, LL (dashed line) is the load limit opening, GV (solid line) is the guide vane opening, and WS (solid line) is the rotational speed of the water turbine. ST is the start time point of the start command to the water turbine, RT is the start time point of the water turbine, and PL is the time point when the generator enters the electric power system in parallel. Further, S is the starting opening of the guide vane (the opening of the guide vane when the turbine is started), RS is the rated rotational speed of the turbine, and NL is the no-load opening of the guide vane.

Next, referring to FIG. 3, a brief description will be given of the three relations of the load limiting opening LL, the guide vane opening GV, and the rotational speed WS of the conventional turbine at the time of starting the turbine. When a start command is given to the water turbine at the time ST at the time of starting the water turbine, first, the load limit opening LL of the load limiting device is increased to the start opening S of the guide vane, and the guide vane control device is used. The guide vane is opened toward the starting opening S at a predetermined speed, and the amount of flowing water introduced into the turbine is gradually increased. However, the turbine remains stopped, the guide vane opening is further increased, and the turbine starts for the first time at the time point RT at which the starting opening S is reached.

When the turbine starts and starts to rotate, the governor's speed-regulating function gradually accelerates the turbine to reach a predetermined speed, and then the guide vane closing direction control is started to set the turbine speed to its rated rotation speed. The guide vane is suddenly closed to the no-load opening NL so as not to overshoot, and the turbine continues to rotate at the rated rotation speed RS. After that, the generator is excited to establish a voltage to synchronize with the power system, and the generator is synchronously inserted into the power system at time PL. During this time, the load limit opening LL is maintained at a constant value (starting opening S of the guide vane).

Next, in order to control the load of the generator, it is necessary to set the upper limit of the setting by the guide vane control device, and a continuous "increase" command is given to the speed governing / load setting device. In this way, the guide vanes are rapidly opened to the load limit opening, and the generator takes the load corresponding to the guide vane opening. After that, the guide vane is gradually opened by the "increase" command along the load limiting opening LL, and reaches the automatic load adjusting target opening AL by the automatic load adjusting device described later, and the generator is set to the guide vane. Gradually increase the load according to the opening.

[0008] By the way, there are cases where the river water level increase rate due to the operation of a hydroelectric power plant is regulated by the River Law. When starting discharge, it is necessary to keep the rate of rise of water level low. For the above reasons, if the above-mentioned guide vanes are opened to the starting opening S to start the water turbine and the generators are synchronously inserted in parallel and started by the conventional starting method that takes load, the discharge rate increase rate becomes too large. I sometimes touched the river law.

As a countermeasure against this, when the turbine starts to rotate at the time of start-up, the load limit is lowered to near no load, or after the generators are synchronously inserted in parallel, the speed governing / load setter is gradually used by using an interrupter. It was controlling to raise. In addition, in the recent automatic load adjustment device (hereinafter referred to as ALR), the load control device is controlled, but the river method is taken into consideration, and the control amount is reduced when the load is small. Some have the function to do.

[0010]

[Problems to be solved by the device]

 In the control to lower the load limit to near no load as a measure to prevent the river law from being touched, the no load position (opening) changes due to the head difference at power plants with large head fluctuations. Therefore, the problem is that it becomes difficult to adjust the no-load position of the load limiting device. Also, in the control method in which the speed governor / load setting device is gradually increased using an interrupter, ALR and control compete, Since the control speed of the governor / load setting device is slow, continuous detection of ALR difference or detection of control congestion may cause ALR control to be locked and maintain the current state, which was a problem. The present invention has been made to solve the above-mentioned problems, and when load control is performed in consideration of the River Law at the time of starting the power turbine, the load limiting device for the power turbine that does not touch the River Law. Aim to get.

[0011]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention comprises a power generation turbine, a turbine generator that is rotationally driven by the power generation turbine, and a guide vane control device that controls opening and closing of a guide vane of the power generation turbine. In a hydroelectric power station, the guide vane control device is incorporated into the load limiting device that limits the opening of the guide vane, and immediately after the turbine generator is connected to the electric power system, the guide vane is inserted. It is characterized by presetting the opening that the turbine should take and controlling the discharge rate of the turbine to the river from the minimum flow rate.

[0012]

[Action]

 When the generator was put into the electric power system in parallel during start-up control of the turbine, the load limit was lowered to a preset value and the load limit was gradually increased from this position according to the discharge amount. It is possible to control the starting of the water turbine without touching.

[0013]

【Example】

 Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a main part of an embodiment of a load limiting device for a power generation turbine according to the present invention. FIG. 2 shows an example of a start control time chart when the water turbine is started by the device, and the corresponding parts in FIG. 3 are designated by the same reference numerals. In FIG. 1, a device surrounded by a dash-dotted line and denoted by a reference numeral 10 is a load limiting device for a power generation turbine according to the present invention. The device 10 includes an on-state change detection circuit (hereinafter referred to as an on-state change circuit) 11, a counter 12, and a low value priority circuit 13. Reference numeral 20 denotes a detector (indicated by a contact for convenience of explanation) for detecting that a generator (not shown) has been inserted in parallel in the power system, and the detection signal 20a thereof is applied to the on-state transformation circuit 11. The on-state change circuit 11 produces an output 11a only when the detection signal 20a is received, and the output 11a is added to the counter 12 as a preset command signal. Reference numeral 21 is an increase / decrease command contact of a guide vane control device (not shown), and the increase / decrease command is added to the counter 12. Reference numeral 22 is a preset value (no-load opening) that defines the opening of the guide vane output from the guide vane control device, and is added to the counter 12. Reference numeral 12a is an output of the counter 12 and is added to the low value priority circuit 13. Reference numeral 23 is a speed signal output from a guide vane control device (not shown) and is added to the low value priority circuit 13. The low value priority circuit 13 compares the output 12a of the counter, which is two inputs, with the speed signal 23, selects one of the two, whichever is lower, and outputs it as the load limiting output 13a. To do.

Next, the operation of the device of the present invention having the above-mentioned configuration will be described with reference to FIG. 2 in which the corresponding parts in FIGS. As is clear from the comparison between FIG. 2 and FIG. 3, it is the same as the conventional device until just before the synchronous parallel insertion of the generator into the system. That is, a start command is given at the time point ST, and the load limit opening LL is increased to the start opening S of the guide vane by the "increase" command of the increase / decrease command contact 21 of the guide vane control device, and Machine). When the turbine reaches the rated rotation speed RS, it excites the generator to establish a voltage and establishes synchronization with the power system. At time PL, the generator is synchronously inserted into the power system.

When the generator is synchronously paralleled to the power system, the detector 20 detects it and closes its a contact to output a detection signal 20a, which is applied to the on-state change circuit 11. . Upon receiving the detection signal 20a, the on-state change circuit 11 produces an output 11a, which is applied to the counter 12 as a preset command signal. A preset value 22 that determines the opening of the guide vane (no-load opening) is previously input to the counter 12 from the guide vane control device, and when the preset command signal 11a is received, the counter 12 Is set to a preset value (no-load opening) 22, and this preset value is added to the low value priority circuit 13 as the output 12a of the counter 12. On the other hand, since the speed signal 23 is added to the low-value priority circuit 13 from the guide vane control device (not shown), when the output 12a is added from the counter 12, the low-value priority circuit 13 receives both inputs. The lower value (no-load opening) is selected and output as the load limit output 13a. Therefore, as shown in FIG. 2, at the time point PL when the generator is synchronously inserted in the electric power system, the load limit opening LL is controlled to descend to a position that matches the no-load opening NL.

After that, an “increase” command is given by the increase / decrease command contact 21 of the guide vane control device to gradually increase the load limit opening LL, and by ALR in consideration of the river method, or by manual operation or the like. In response to the external increase / decrease command, the load control of the generator is performed within the load limit opening LL. Therefore, it is possible to start the water turbine without touching the river law when starting it.

[0017]

[Effect of device]

 As described above, the present invention has been described in detail. According to the present invention, even if there is a fluctuation in the head of a hydroelectric power plant whose discharge rate change rate is regulated by the River Law, it is completely eliminated. Since the load can be controlled from the load position, it becomes easy to control the discharge rate, and it is possible to obtain a load limiting device for a power generation turbine that enables the turbine to be started without touching the river law.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an addition device to a load limiting device of a power generation turbine according to the present invention.

FIG. 2 is an example of a start control time chart when the turbine is started by the apparatus shown in FIG.

FIG. 3 is a start control time chart of a conventional water turbine.

[Explanation of symbols]

 10 ... Additional device to load limiting device, 11 ... ON state change detecting device, 12 ... Counter, 13 ... Low value priority circuit, 20 ... Synchronous parallel detector, 21 ... Increase of load limiting device・ Reduction command contact, 22 …… Preset value, 23 …… Speed signal.

Claims (1)

[Scope of utility model registration request] 1. A hydroelectric power plant comprising a turbine for power generation, a turbine generator rotatably driven by the turbine for power generation, and a guide vane control device for controlling the opening and closing of a guide vane of the turbine for power generation. , A load limiting device incorporated in the guide vane control device for limiting the opening degree of the guide vane, the opening degree that the guide vane should take immediately after the turbine generator is put in parallel in the power system. A load limiting device for a power generation turbine, which is preset, and the discharge rate of the turbine to the river can be controlled from the minimum flow rate.