JPS5938506A - Automatic speed increaser for turbine driving feed pump - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention sets the rotational speed of a turbine-driven water feed pump (T-BFP) to a rotation speed corresponding to a point at which water can be supplied to a steam generator (hereinafter abbreviated as "water supply starting point"). This invention relates to an automatic speed-up device for a turbine-driven water pump that can automatically speed up up to a maximum speed.

The conventional T-BFP speed increase method was to increase the rotation speed of the driving turbine to a predetermined constant target value, but in this method, the discharge pressure of 'I' - BFI) The disadvantage is that it is necessary to further increase the rotation speed at the point to overcome the water supply pressure after the outlet merges, that is, the rotation speed corresponding to the water supply start point of the '1'-BFP, and the transition to water supply control is not smooth. was there.

FIG. 1 is a diagram showing system head characteristics of a water supply system. In the case of a constant pressure operation plant, since the curved edge of the system head is flat, the change in discharge pressure due to i'-BFP rotational speed change is small, and the rotational speed target ([i
The influence of the above-mentioned drawback is small even if . However, in the case of a variable pressure operation plant, the main steam pressure changes depending on the load, so the system head of the water supply system changes more significantly than in constant pressure operation. Therefore, especially in the case of a variable pressure operation plant, the T-BFP rotational speed corresponding to the feed water start point is not uniformly determined, and it is not preferable to set the target speed to a constant value. In Fig. 1, curve A is the pump R-H characteristic, curve 1MB is the system head characteristic of a constant pressure operation plant,
Curve C is a system head characteristic curve for a variable voltage operating plant.

The purpose of the present invention is to increase the rotation speed of the T-BFP to a point equivalent to the full water supply start point, regardless of changes in the system head of the water supply system, thereby enabling a smooth transition to subsequent water supply control. There is a full range of quick equipment on offer.

The present invention calculates the rotation speed corresponding to the starting point of water supply from the water supply pressure detected at the water supply pump outlet confluence section and the pump characteristics,
Adopting a variable setting method that uses the rotation speed as the set value, T-R
This is to increase the speed of FP.

An embodiment of the present invention will be described below with reference to the drawings.

Figure 2 shows the piping system around the water supply pump.
1 is a T-RFP, which is driven by a steam turbine 2. In addition, 3 is a motor-driven water supply pump (hereinafter 1'-M-
(abbreviated as BFPJ) and is driven by a motor 4.

5, 6, and 7.8 are T-B F I) outlet check valve, stop valve, and M-BFP outlet check valve, stop valve, respectively. When starting the plant, water is supplied to the reboiler by M-BFPaK, and after reaching the specified load, T-BFPI is started and the water supply load is reduced to T-BFF.
and then the second 'l' -B 1
” P is added, but when starting T-BFPI,
As mentioned above, it is desirable to increase the speed to a rotational speed corresponding to the starting point of water supply and keep it on standby so that a smooth transition to water supply control can be made. Reference numeral 9 denotes a pressure detector for carrying out this operation, and the detailed control system will be explained with reference to FIG.

In FIG. 3, a signal 15 includes an actual rotational speed signal 13 detected by the T-BFP rotational speed detector 12 and a rotational speed setting value 11.
is the deviation calculated by the subtractor 14, and this deviation signal drives the control valve actuator 20 of the BFP driving turbine, which is the operating end, through the proportional calculator 16 and the proportional integral calculator 19, and the rotation speed is increased up to the set rotation speed. speed up.

Reference numeral 17 denotes a rotation speed change rate setter, and its purpose is to limit the change rate when the deviation between the actual rotation speed and the target rotation speed at the initial stage of speed increase is large by the low position selector 18.

The feature of the present invention is that, as mentioned above, the rotation speed setting value 11 is made variable, and the rotation speed of the T-BFP is increased to a point corresponding to the pressure of the RFP discharge merging section. Reference numeral 9 represents a pressure detector installed at the BFP outlet confluence section as explained in FIG. 2, and 10 represents a function generator. The function generator 10 has a relationship between the discharge pressure and the pump rotation speed determined from the pump characteristics as a function, and the pressure detector 9
By adding P + ΔP, which is the sum of the margin ΔP (piping loss, etc. > 1) to the detected pressure P, the target value rotation speed li
This makes it possible to set the rotation speed to overcome the 13FP discharge confluence pressure.

Therefore, according to an embodiment of the present invention, the rotational speed of the T-RFP can be increased to a point where the BFP discharge discharge confluence direction pressure is overcome, that is, equivalent to the point at which the water supply starts flowing out.

According to the present invention, regardless of changes in the system head of the water supply system (regardless of the required start-up timing of the T-RFP), the T-RFP
The rotational speed of the RFP can be increased to a point equivalent to the water supply start point, which has the effect of smoothing the transition to the subsequent water supply control.

[Brief explanation of the drawing]

Figure 1 is the system head IFI diagram of the water supply system, and Figure M2 is the turbine drive system of the present invention! 4I] Piping system diagram around the cap water pump in an example of automatic speed increase setting of the water supply pump, Figure 3 is i' -
It is a block diagram of speed increase control of BFP.

Claims (1)

[Claims] 1. In a power generation plant that has a water supply pump for the purpose of supplying water to a steam generator and a turbine for driving the water supply pump, and is equipped with a speed increase device for the turbine-driven water supply pump, downstream of the water supply discharge valve of the T-BFP. A turbine-driven water feed pump characterized in that the rotation speed at which T-BFP feed water can be supplied to the steam generator is determined based on the pressure detected by a pressure detector installed in the pump, and the speed is increased using the rotation speed as a set point. Automatic speed increase device.