In the modern energy industry, steam turbines are core power equipment, and their safe operation is directly related to the stability of the power grid and economic benefits. When the unit encounters critical conditions such as overspeed and abnormal oil pressure, the pressure switch RC771BZ097Z, as the “nerve endings” of the steam turbine safety system, becomes a key component to block the expansion of accidents through precise pressure monitoring and extremely fast response mechanism. Below we will deeply analyze the working principle of the pressure switch and its core role in the steam turbine protection system, revealing how it can achieve fast trip protection with a millisecond response speed.

1. The technical core of the pressure switch RC771BZ097Z: a precision device for mechanical-electrical signal conversion

The pressure switch RC771BZ097Z adopts a mechanical structural design, which is mainly composed of three parts: pressure sensing element, spring assembly and micro switch. Its core working principle is: when the pressure of the control oil changes, the pressure sensing element produces displacement, and through the balance relationship between the spring preload and the set pressure, the contact action of the micro switch is triggered, thereby outputting an electrical signal.

Technical highlights:

High-precision adjustment: By adjusting the screw to change the spring preload, the switch point can be accurately set to meet the needs of different working conditions.

Anti-interference design: The damping hole structure is used to buffer pressure fluctuations and avoid false triggering.

Dual contact configuration: Normally open (NO) and normally closed (NC) contacts are optional, suitable for series or parallel protection logic.

2. Tripping protection logic of steam turbine safety system: triggering scenarios and chain reactions of pressure switches

The steam turbine safety system (AST) implements protection by monitoring key parameters such as overspeed, oil pressure, and vacuum, and the pressure switch RC771BZ097Z mainly undertakes the monitoring tasks of the following scenarios:

Bearing oil pressure low trip

When the lubricating oil pressure of the thrust bearing or radial bearing is lower than the set value, the pressure switch is activated, triggering the AST solenoid valve to lose power. At this time, the high-pressure fire-resistant oil leaks, and the main steam valve and regulating valve of the steam turbine are closed within 1~2 seconds, cutting off the steam inlet.

Anti-fire-resistant oil pressure abnormal protection

The fire-resistant oil pressure is a key parameter for controlling the opening of the steam valve. If the pressure switch detects a sudden drop in fire-resistant oil pressure, it will immediately send a signal to the emergency trip control block to synchronously close the AST and OPC solenoid valves to achieve double insurance.

Vacuum system failure protection

When the condenser vacuum is lower than 80kPa, the pressure switch triggers an alarm and interlocks the shutdown to prevent the low-pressure cylinder from overheating and damage.

Chain reaction process:

Pressure switch → ETS (electronic trip system) → AST/OPC solenoid valve power failure → oil leakage → steam valve closure → unit shutdown.

3. Implementation mechanism of ultra-fast tripping: millisecond response from pressure perception to mechanical action

The turbine trip protection requires a response time of ≤0.5 seconds. The pressure switch RC771BZ097Z achieves ultra-fast response through the following design:

Direct monitoring of key paths

The pressure switch is directly installed on the oil pressure pipeline or vacuum cavity to eliminate signal transmission delay. For example, the bearing oil pressure switch is close to the oil pressure sensor to capture pressure changes in real time.

Instantaneous action of mechanical structure

When the pressure exceeds the set threshold, the spring drives the piston to move, the micro switch contacts complete the switching within 0.1 seconds, and the electrical signal is directly transmitted to the ETS through hard wiring.

Redundant design ensures reliability

Each monitoring parameter is configured with a dual-channel pressure switch (such as high and low pressure sides), and the trip is performed only when the two signals are triggered at the same time to avoid single-point fault malfunction.

4. Collaboration with turbine protection system: integration and optimization of pressure switch

In modern turbine control systems, the pressure switch RC771BZ097Z needs to be deeply coordinated with the following subsystems:

DEH (digital electro-hydraulic control system)

The pressure switch signal is used as an input parameter of DEH to participate in the speed control and load distribution logic. For example, when the oil pressure is abnormal, DEH automatically reduces the load and prohibits speed increase.

TSI (turbine monitoring instrument)

Linked with the speed sensor and vibration monitoring device to form a multi-dimensional protection network. When the oil pressure is low and the speed is abnormal, an emergency shutdown is triggered.

Manual intervention interface

The pressure switch signal is connected to the manual shut-off valve control circuit, and the operator can force shutdown through the local button.

The pressure switch RC771BZ097Z has become the “last line of defense” of the steam turbine security system with its precise mechanical structure, millisecond response capability and multiple redundant design. In the future, with the development of intelligent technology, this component may integrate pressure sensors and microprocessors to achieve fault self-diagnosis and predictive maintenance, further improving the safety of the unit. In the context of energy transformation, the technical iteration of this core component will continue to safeguard the stable operation of the power system.

When looking for high-quality, reliable pressure switches, YOYIK is undoubtedly a choice worth considering. The company specializes in providing a variety of power equipment including steam turbine accessories, and has won wide acclaim for its high-quality products and services. For more information or inquiries, please contact the customer service below:

E-mail: sales@yoyik.com
Tel: +86-838-2226655
WhatsApp: +86-13618105229

Yoyik offers various types of spare parts for steam turbines, generators, boilers in power plants:
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