**Sheng Xu Provides: The Basic Principles of Microcomputer Relay Protection Calibrator**
**1. What is the Function of Relay Protection and Safety Automatic Devices?**
Relay protection and safety automatic devices play a critical role in power systems by detecting abnormal conditions or faults and responding accordingly. When a fault occurs—such as a short circuit, overcurrent, or equipment failure—the system sends an alarm signal to the monitoring personnel or directly triggers a trip command to the circuit breaker. This action helps prevent further damage, ensures the stability of the power system, and minimizes disruptions to power supply. These devices are essential for maintaining the reliability and security of electrical networks.
**2. What is the Task of Relay Protection in the Power System?**
The primary task of relay protection is to detect and isolate faulty components quickly and accurately. When a fault occurs within a protected area, the relay protection system must issue a trip command to the nearest circuit breaker, disconnecting the faulty section from the rest of the network. This minimizes damage to equipment and reduces the impact on the overall power supply. Additionally, relay protection also monitors abnormal operating conditions, such as overloads or voltage fluctuations, and alerts operators or initiates automatic adjustments. In some cases, these systems may allow a short time delay before taking action, depending on the severity of the condition.
**3. Commonly Used Relay Protection Types**
- **Current Protection**: This type of protection activates when the current increases due to a fault. It typically includes three stages: instantaneous overcurrent, time-delayed overcurrent, and inverse-time overcurrent.
- **Distance Protection**: This method measures the impedance between the relay location and the fault point to determine if a fault has occurred.
- **Differential Protection**: Compares the currents entering and leaving a protected zone to detect internal faults.
- **High-Frequency Protection**: Injects high-frequency signals into transmission lines and compares the received signals to determine if a fault is internal. This method does not interfere with normal power transmission.
There are two main types of high-frequency protection: **blocking type**, where signals are continuously sent to prevent tripping unless a fault is detected, and **permissive type**, where signals are only sent when a fault is detected, allowing for coordinated tripping.
**4. Basic Requirements for Relay Protection in the Power System**
Relay protection systems must meet four key requirements: **reliability**, ensuring consistent performance; **speed**, enabling rapid response to faults; **selectivity**, isolating only the affected area; and **sensitivity**, detecting even minor abnormalities. These features ensure that the protection system operates effectively under all conditions.
**Technical Parameters of the Microcomputer Relay Protection Calibrator**
- **Current Source**: AC 0–40A/phase, 0–120A/3-phase parallel; DC 0–30A/phase, 0–90A/3-phase parallel.
- **Power Output**: 400VA/phase.
- **Accuracy**: ≤0.2%.
- **Response Time**: <160μS.
- **Resolution**: 1mA (AC), 2mA (DC).
- **Voltage Source**: AC 0–125V/phase, DC 0–220V/phase.
- **Frequency Range**: 0–1000Hz, with resolution of 0.001Hz.
- **Phase Control**: 0–360°, with 0.1° accuracy.
- **Time Range**: 0–9999.999s, ±1.0ms.
- **Switch Inputs/Outputs**: 7 pairs of dry contacts, 3 pairs of dry contacts for output.
- **Power Supply**: 120–250VAC, 50/60Hz.
- **Dimensions**: 450mm × 150mm × 370mm.
- **Weight**: 11kg.
**Main Features of the Microcomputer Relay Protection Calibrator**
This device is equipped with a **DSP-based intelligent host**, offering high-resolution waveform generation with 2000 points per cycle. It supports both standalone operation and PC connectivity, allowing users to run comprehensive tests through intuitive Chinese software. The device includes a **large LCD display**, making it easy to operate without requiring advanced computer skills. It also features a **photoelectric rotary mouse**, simplifying control. With a **switching power supply** and **modular design**, it is compact, lightweight, and easy to maintain. Additional features include **GPS synchronization**, **Comtrade file playback**, and **power factor correction** for improved efficiency. The calibrator can simulate various fault scenarios, including transient and permanent faults, making it ideal for testing complex protection systems.
Classic Radiator Valve
Ningbo Safewell Plumbing Co., Ltd. , https://www.safewellbrass.com