The Rapid Pressure Rise relay serves as a crucial safety device designed to monitor changes in the internal pressure of oil tanks in various electrical equipment, including transformers, capacitors, and reactors. This relay consists of two main components: the sudden pressure relay (or pressure gradient relay) and the static hydraulic relay. These mechanisms work together to provide essential signals for the protection of fuel tanks.
When the internal pressure of the tank rises at a rate exceeding 3 ± 1 kPa/sec, the sudden pressure relay is activated, indicating that the tank was at risk during critical incidents related to low pressure. The relay’s response speed is adjusted to enhance its operating characteristics, as illustrated in the provided figure. The relay operates effectively when the pressure change is within the acceptable limits, ensuring that conditions remain safe during operation.
In scenarios where the pressure rises but remains normal (less than 3 ± 1 kPa/sec), the relay functions as intended, ensuring continued safety for the fuel tank. Additionally, this relay integrates a static hydraulic pressure switch that provides alarm signals when the oil pressure drops below predetermined thresholds.
The sensitivity of the rapid pressure rise relay is set to monitor pressure levels, with specific control parameters for oil tanks below 25 kPa ± 20%. If the pressure gradient exceeds these levels, the relay’s response time decreases significantly, allowing for rapid detection. For instance, if the pressure increases to a gradient of 500 kPa/sec, the relay’s movement response time is just 0.05 seconds. In contrast, a pressure increase to a gradient of 100 kPa/sec will trigger a response time of 0.25 seconds. This swift detection mechanism is vital for ensuring the safety and reliability of the equipment.
When the rate of pressure increase is below 3 ± 1 kPa/sec, the relay does not activate in response to the sudden pressure changes, as it meets the performance criteria for low-pressure alarms associated with electrical incidents. In such cases, the risk of damage resulting from an incident is minimal, allowing the static hydraulic mechanism to manage the pressure effectively. This approach helps prevent unnecessary economic losses that could arise from low pressure in the oil tank of a transformer. Thus, it is advisable to rely on the static oil pressure alarm or utilize trip signals for sudden pressure relays when this product is in operation.
Usable Range
1. Range: Suitable for oil-immersed transformers, power capacitors, reactors and other enclosed oil-immersed electrical fuel tank;
2. Environmental requirements: -30 ℃ ~ +50 ℃;
3. Relative humidity: +20 ℃, the less than 95%;
External Dimension Drawing
Feature
● High Sensitivity: The RPRR is calibrated to detect pressure changes within a defined range, with a net pressure increase value generally not exceeding 25 kPa. This sensitivity is critical for timely intervention during rapid pressure changes.
● Dual Protection Mechanism: By integrating both sudden pressure and static pressure monitoring, the RPRR provides a comprehensive protective solution, ensuring reliable operation even under varying conditions.
● Robust Design: The RPRR features a double isolation bellows, which enhances its reliability and accuracy, making it a dependable choice for use in transformers.
● Micro-switch Technology: The use of highly reliable micro-switches ensures effective contact transformation under operational conditions, maintaining consistent performance.
Installation Guidelines
1. The pressure and burst pressure relay should be attached via a butterfly valve with an 80 mm diameter installed on the side wall of the oil tank. It is recommended to keep the height of this installation at H meters, as shown in Figure 4. If the distance from the valve exceeds 3 meters, adjustments to the installation specifications should be made accordingly.
2. Proper installation is crucial; ensure the relay is securely mounted to prevent any installation faults or misalignments.
3. For optimal performance, the pressure and burst pressure relay ought to be installed horizontally on the oil tank to permit the accumulation of gas at the upper section. Make sure to connect it to the designated gas outlet, as illustrated in Figure 2.
4. It is imperative to connect the relay accurately to the power source and to verify that it is functioning under the appropriate operational parameters.
5. Calibration of the device is essential; the gas pipeline should connect one end to the pressure gauge while the other connects to a monitoring system. This setup helps maintain low flow rates and allows for accurate pressure monitoring.
6. Periodic testing of the product is advised, which includes specific examinations via the relief valve depicted in Figure 4. This is to assess its functionality. Should the relay fail to fulfill the required specifications, timely maintenance or replacement should be considered.
7. When using the oil outlet pipe for venting gas (refer to Figure 4), ensure a proper line of connection and keep the outlet unobstructed to avoid any bottlenecks.
8. It is important to open the valve to enable oil drainage, ensuring that the relay does not experience any blockages during this operation.
9. Throughout the transfer procedure, the pressure and burst pressure relay should not be placed directly on any pressure apparatus. Take precautions to avoid circumstances that could lead to damage.
10. The pressure and burst pressure relay conforms to established standards. Therefore, any unauthorized alterations or disassembly by users are strictly forbidden.
Relay Testing Procedures
Relay testing can be categorized into two primary types: routine and performance assessments.
1. For routine assessments, a simplified testing setup can be utilized alongside product detection equipment (see Figure 5). The following steps outline the air release testing process:
(1) Begin by ensuring that the valve linking the relay to the transformer is closed, confirming that the electrical circuit remains intact;
(2) Verify the connection of the joint experimental pump to the discharge piping;
(3) Remove the safety cap from the bleed plug and unscrew it to access the relay interface;
(4) Activate the pump to release air 4 to 5 times, carefully monitoring the reaction of the relay. It should operate normally without triggering any alarms for faults.
2. For performance evaluations, follow these steps:
(1) Start by closing the valve, then disconnect the relay from the oil draining system and remove the relay altogether;
(2) Conduct a thorough inspection of the relay after removal to determine its operational state. If any issues are identified during these checks, a new relay should be installed, and defective units should be returned to the manufacturer for servicing.
