Abstract: A control loop for regulating the magnitude of a variable quantity of an apparatus to a reference value, for example the steam pressure in the output line from a boiling water reactor, wherein the instantaneous magnitude of the steam pressure is compared with a reference value and the difference therebetween is used to regulate a valve in the steam line in such manner as to eliminate the difference. The control loop also includes one resonance filter for the regulating medium whose resonant frequency coincides with the frequency at which the control loop, in the absence of such a filter, would become unstable.

Abstract: An overspeed protection controller (OPC) which is incorporated as part of a turbine speed/load control system for the purposes of controlling the monitored speed of a steam turbine at a first predetermined speed valve subsequent to an OPC activation is disclosed. The governor and interceptor valves of the steam turbine are positioned controlled by a set of electrohydraulically operated valve position servo systems. The OPC provides for rapid hydraulic closure of each valve when activated by either a detection of an interruption of generated electrical power flow to a power system load when the generated electrical power is greater than a predetermined value or the detection of the monitored turbine speed being greater than a second predetermined speed value. The rapid closure of the valves results in an interruption of steam flow to the high and lower pressure turbine sections of the turbine system which causes steam energy to be trapped in the reheater which is disposed between the turbine sections.

Abstract: The invention concerns a feedback control method for controlling the starting of a steam turbine unit comprising a reheater, a turbine by-pass system consisting of a HP-by-pass system and a LP-by-pass system, at least one regulating valve for the HP-by-pass system, at least one regulating valve for the LP-by-pass system, at least one inlet valve for the HP-turbine, at least one intercept valve for the MP/LP-turbine and a governing device to regulate the turbine speed or power output, according to which method during no-load and low-load operation and up to a predetermined partial load the pressure within the reheater is regulated by a first feedback control device with the LP-by-pass regulating valve acting as positioning element in such manner that a greater quantity of steam will flow through the HP-turbine than through the MP-turbine, and a smaller quantity of steam through the HP-by-pass system than through the LP-by-pass system, whereby a maximum permissible HP-exhaust steam temperature will not be excee

Abstract: An arrangement for the storage of energy in power plants in which an excess of water during low-load operation is heated in feed water preheaters, and is stored as hot water in a hot storage vessel. During peak-load operation, the hot water from the storage vessel is fed into a feed water line, bypassing the feed water preheaters. Alternately with the hot water, colder water is taken from or stored in the lower portion of the hot storage tank. Before being fed into the hot storage tank, the colder water is thermally degassed with bleeder steam at a pressure slightly above atmospheric pressure, preferably between 1.01 and 1.5 atmospheres (abs). The feed water tank connected to the degasser is used for volume compensation while storing the hot water in the hot water storage tank. The storage tank may be in the form of three units of substantially identical volume. The hot storage tank and the feed water tank used as warm-water storage, are alternately filled and emptied.

Abstract: An improved high-water-level trip control for a steam turbine is disclosed. Instead of causing a trip of the turbine (or reactor) based merely on the water level in the steam generator, the present invention generates a trip command that is based on a function of more than one parameter. Such a function more accurately indicates the quantity of water droplets in the steam leaving the steam generator than a function of a single parameter does. In particular, it is disclosed to trip the turbine when the water level exceeds a variable reference that increases as steam velocity decreases; this takes into account the effect of steam velocity on the entrainment of water droplets by the steam.

Abstract: At the point of time to when the turbine speed has come up to a first speed N.sub.1, a thermal stress expected in the turbine when the speed is increased to a second speed N.sub.2 at a rate .alpha..sub.1 is presumed. Thermal stress .sigma..sub.s(t) -.sigma..sub.sT1 at the point of time t.sub.o1 for commencing acceleration to the second speed N.sub.2 is then obtained, which point of time t.sub.o1 would never cause the maximum value of the presumed thermal stress to exceed a predetermined limit .sigma..sub.sl of the thermal stress when the turbine speed is increased at that rate. Then, a length of time T.sub.w1, referred to as a warming time, is determined which is required for the thermal stress .sigma..sub.s(t) to decrease to the level of (.sigma..sub.s(t) -.sigma..sub.sT1) when the warming is continued after the point of time t.sub.o. Subsequently, a length of time (N.sub.2 -N.sub.1)/.alpha..sub.1 required for increasing the turbine speed from N.sub.1 to N.sub.2 at the rate .alpha..sub.1 is calculated.

Abstract: A vapor generating system for use in a power plant having a steam turbine and a condenser connected in a series flow relationship, in which a vapor generating section receives a heat exchange fluid and passes the fluid in a heat exchange relation to a source of heat to raise the temperature and pressure of the fluid to predetermined values. The vapor generating section operates at substantially constant pressure during start-up and a pressure control station is provided which includes one or more relatively small bore tubes, a first conduit having control means disposed therein, and a second conduit, through which fluid passes before it is passed to a plurality of separators in the main flow path which receives the fluid and separates same into a liquid and a vapor. The separators are connected to a vapor circuit and to a liquid circuit for passing the vapor and liquid to the turbine and heat recovery or condenser, respectively. A method of starting up a vapor generating system in a power plant.

Abstract: A steam turbine control system comprising a primary and an auxiliary manual turbine controller, each said turbine controller including a set of valve position setpoint controllers for close-loop control of the turbine steam admission valves, is disclosed. Each valve position setpoint controller operates, at times, on a position error signal to generate a valve position control signal which controls the rate of valve position movement of a corresponding turbine steam admission valve. The steam admission valves are closed-loop controlled by a selected set of said primary and auxiliary valve position setpoint controllers. The set of valve position control signals corresponding to the selected set of position setpoint controllers are coupled to their respective turbine steam admission valves for controlling the rate of position movement therein. The valve position error and position control signals of the unselected set of said controllers are maintained at approximately zero potential.

Abstract: An electrohydraulic system for rapidly reducing the steam flow through the high pressure and lower pressure stages of a turbine power plant in response to a partial loss of electrical load, is disclosed. In response to the detection of a partial loss of load, the system provides for controlling a portion of the governor valves and all of the interceptor valves to close rapidly and independently of the turbine control system; also to operate the turbine control system to cause the remaining governor valves to operate to a predetermined partially closed condition independent of the normal governor valve reference demand signal by applying a signal for changing the open limit position of the governor valves; and to eliminate the affect of the impulse pressure loop from the turbine control system. The upper valve position limit signal and the slower rate of change reference demand signal is matched to the applied signal.

Abstract: In the improved supply circuit, provision is made for a "start-up" storage tank placed at a higher level than the heat exchanger and connected to a secondary circuit in portion of this latter which is located between the solar engine and the feed pump and includes the evaporator. The storage tank is equipped with heating means for bringing the fluid contained therein to a temperature which is lower than the temperature of the fluid within the evaporator.

Abstract: Method and apparatus for controlling the set point for steam temperatures for cold start-up of a steam generator-turbine unit wherein inlet steam temperature and turbine load absorption are steadily and substantially simultaneously increased in accordance with a predetermined relationship so as to reach their final values substantially synchronously.

Abstract: A steam turbine installation includes a safety system located in the steam flow path having a stop valve located in the steam flow path upstream of the turbine and a vacuum break valve located in the stream flow path downstream of the turbine, and a combined regulating and safety device connected to the turbine produces signals for controlling these valves. In addition, a signal from a steam flow monitor located downstream of the stop valve is supplied to a logic system, this signal having a value which normally corresponds to the setting of the stop valve. In the event of a disparity the logic system functions to trip the regulating and safety device which results in a closure of the stop valve and a partial opening of the vacuum break valve.

Abstract: A once-through boiler is provided with integral separators with which drain valves are associated. Boiler inlet and outlet flows are balanced throughout startup first by drain valve control in response to separator level and then by drain valve control in response to throttle pressure.

Abstract: In an ocean thermal energy conversion system utilizing solar energy stored as heat in tropical waters to generate electricity, the evaporating and condensing functions of the heat exchangers are interchanged in order to prevent the accumulation of micro-organisms on their surfaces. The surfaces of the heat exchangers are also mechanically brushed or scraped so as to remove any thin films of microbial slime. In order to remove additional micro-organisms from the surfaces of the heat exchangers, the flow of hot and cold sea water through each of the heat exchangers is interchanged preferably on a daily basis. Thus, micro-organisms from the warm surface waters that attach themselves to one heat exchanger surface will be destroyed by the cold water that flows through that heat exchanger on the next day. On the other hand, the organisms that live in the cold water at great depths cannot survive the next day's warm water environment which is caused by alternating the flow to the two heat exchangers.

Abstract: A method and apparatus for testing the movability of a valve plug. The invention provides for movement of the valve plug from a first to a second position, from the second to a third position in an opposite direction, and again in the first direction to the first position. Indicators are provided to ascertain if such movements have occurred. Alarm signals are generated if any of the movements do not occur. The magnitude of the motions of the plug is normally small relative to the full valve stroke. Size of stroke and time at each position are chosen to minimize any disturbance to the power system.

Abstract: Condensate purification such as demineralization, filtration or sterilization for use in a power plant of the type having at least one main condenser with a hot well as part of the steam cycle and in which the condenser is connected to receive steam from a turbine generator and the hot well is connected to discharge to a main condensate pump. Purification of the condensate is executed with improved method and apparatus comprising a side stream demineralization system. The improvement includes a baffle mounted within said main condenser defining an upstream portion of the condenser on one side of the baffle and a downstream portion of the condenser on the other side of said baffle. The condenser hot well is located on the downstream side of the baffle. A passageway is defined over the baffle for flowing fluid therethrough to the hot well. The passageway includes a weir cooperatively disposed therewith on the upstream side of the baffle to hold back a pool of fluid from flowing through the passageway.

Abstract: A steam turbine construction wherein the turbine rotor shafting is mounted in bearing means located in the end walls of the turbine housing and wherein the bearings are lubricated with water condensed from the working steam supplied to the turbine. The lubricant flows in a re-circulating system tapped from the condensate-return line leading back to the boiler from the condenser after the turbine has been started and is supplying power, and an auxiliary supply of lubricant water is taken from a reserve gravity flow tank to supply water to the bearings during the starting and stopping runs of the turbine.

Abstract: A hybrid digital computer gas turbine power plant control system which may operate in a multiple-control loop arrangement is provided with selected process variable monitoring means. Control system inputs representative of current values of such variables are continuously available to provide positive highly responsive control over a broad range of gas turbine operating conditions. Predictable process sensor errors are effectively eliminated by means of programmed computer operations to thereby insure highly accurate control variable derivation essential to maintaining gas turbine operation at or near design limits.

Abstract: A digital computer system for automatically controlling a turbine power plant without operator intervention is disclosed. The system controls the turbine from rolling off turning gear, through heat soak, wide range speed control, and the megawatt loading of the generator in accordance with the on-line condition of the turbine and/or generator. The rate of change of magawatt loading as well as the rate of speed under wide range speed control is automatically controlled toward an operator entered target. The I.P. rotor thermal characteristics are determined both in axial and radial directions. The on-line generator capability is determined in load control.

Abstract: A steam turbine control system includes an operator panel and a digital computer which operates the turbine valves through an electrohydraulic control. Turbine speed and load signals and valve position signals are coupled to the computer for use by the computer control loops in developing valve control signals. Two separate displays are provided on the operator panel, one for the speed or load reference and the other for the speed or load demand. Dedicated pushbuttons on the panel enable certain other parameters such as acceleration or load rate or valve position limit to be displayed in the reference display, while other pushbuttons can be used to address and display in the reference or demand display general control system parameters. A mechanism is provided for entering changes into the computer for the various parameters and for displaying such changes in one of the displays.

Abstract: A once-through boiler is provided with integral separators and a plurality of valves for controlling fluid flow during boiler startup. A pressure control generates an open or close signal for all of the valves and a sequence selector responds to the pressure control and a valve-in-operation logic circuit to generate valve selection signals which enable the valves to respond sequentially to the pressure control output.

Abstract: Steam is removed from the steam cycle of a turbine when the back pressure on the turbine exceeds a predetermined level. Heat is then extracted from the removed steam and dissipated in a cooling tower of a cooling system for the turbine's condenser. Increased temperatures in the cooling tower augment thermal fan action, resulting in lower coolant temperatures and limiting the back pressure on the turbine. When the back pressure on the turbine decreases to an acceptable level, the steam is redirected into the steam cycle.In a preferred embodiment, heat is extracted from steam by passing the steam through the high temperature coil of a vapor-absorption generator. The high temperature vapor formed in the generator transfers the heat to the heat dissipating surfaces of a cooling tower or into heat-exchange relationship with an exhaust coolant discharged from a steam condenser.

Abstract: In a steam turbine plant with feed water heaters receiving steam extracted from the turbine to apply in heat exchange with the feed water being supplied to the boiler, the drain water level in the water heaters is monitored so that when the drain level exceeds a predetermined abnormal level, for example due to rupture of the feed water pipes in the feed water heater, steam supplied to the turbine is automatically reduced to runback the load on the turbine, and thereafter the extraction of the steam to the malfunctioning feed water heater from the turbine is stopped and the feed water heater is bypassed with respect to the feed water flowing to the boiler, so that the malfunctioning feed water heater is thus isolated from the turbine plant.

Abstract: As an improved way of effecting fast valving of turbines of power system steam-electric installations of types that incorporate by-pass systems for by-passing steam from a point ahead of the high pressure turbine either directly to the condenser or to the cold reheat line, and in the latter case also from the hot reheat line to the condenser, and where the purpose of employment of fast valving is to improve the stability of power transmission over transmission circuits to which the generators of the installations in question make connection, when stability is threatened by line faults and certain other stability endangering events, the approach of rapidly closing intercept valves at fastest available closing speed in response to a fast valving signal, is supplemented by bringing into effect preprogrammed processes of control valve repositioning, plus intercept valve reopening, so effected as to cause turbine driving power subsequent to generator rotor first forward swing to hold below a preset value that is l

Abstract: A vapor generating system for use in a power plant having a steam turbine and a condenser connected in a series flow relationship, in which a vapor generating section receives a heat exchange fluid and passes the fluid in a heat exchange relation to a source of heat to raise the temperature and pressure of the fluid to predetermined values. The vapor generating section operates at substantially constant pressure during start-up and a pressure reducing station is provided for reducing the pressure of the fluid before it is passed to a plurality of separators in the main flow path for receiving the fluid and separating the fluid into a liquid and a vapor. The separators are connected to a vapor circuit and to a liquid circuit for passing the vapor and liquid to the turbine and condenser, respectively. A method of starting up a vapor generating system in a power plant.

Abstract: In a steam turbine structure, a stuffing box is conventionally provided for the rotor shaft at the shaft passthrough opening in the turbine casing and blocking steam is admitted to the stuffing box. In order to prevent thermal-shock damage to the shaft at the stuffing box during a re-start of the turbine while the shaft temperature is still approximately at its normal operating temperature and while the blocking steam is then temporarily in a wet state, the blocking steam is prevented from reaching the stuffing box, the wet steam being diverted by way of a controllable valve through a by-pass leading to a condenser. After the blocking steam has reached its dry state, the valve closes off the by-pass to the condenser and opens the blocking steam line leading to the stuffing box.

Abstract: Method and apparatus are described that are operative to elevate the temperature of superheated vapor delivered to a turbine, especially during startup of a power plant. A bypass circuit containing a heat exchanger is interposed in the main steam generator evaporative flow circuit whereby regulated amounts of heat are extracted from the plant operating fluid thereby subcooling the same prior to its passage to the evaporator section of the unit. Reduced amounts of steam are thus produced in the evaporator section for a given amount of heat input to the unit and a concomitant increase realized in the temperature to which the steam passed to the superheater is heated.Economies as well as operational advantages are achieved by the production in the heat exchanger of low pressure steam that is usable in the plant to augment steam flow to the low pressure section of the turbine, for soot blowing purposes, and/or for other low pressure steam needs during startup and normal operation of the plant.