Application Analysis of High-Voltage Single-Phase Distribution Transformers in Power Distribution Networks

1. Safety Hazards in Substation Operation

1.1Transformer Failures

Transformers are critical substation equipment and maintenance focal points. Loose/defective components often cause malfunctions, while internal damage (e.g., oil tank impurities/water/bubbles) triggers partial discharge, risking major losses during outages.

1.2 Overvoltage Risks

Outdoor overvoltage threatens equipment. Lightning-induced impulse currents alter transformer electromagnetic energy, and circuit breaker misoperations cause internal grid overvoltage, damaging transformers and devices.

2. Distribution Transformer Technologies

2.1 Microcomputer Protection

With tech advances, microcomputer protection (microcomputer-based) boasts high reliability/selectivity/sensitivity, preserving system data during outages. Its CPU/ROM/flash/RAM protection system safeguards power storage and efficiency. Flash/ROM enhance CPU capability to handle complex faults, integrating comms/protection/monitoring/measurement for automated control.

2.2 Data Acquisition Components

Combining a 14-bit AVD converter (synchronous type) and multi-channel filter, this component offers high accuracy/stability/low power/fast conversion for transformers. Internal high-precision chips adjust errors without external tools. The CPU system includes 16 preset/10 external output switches (10 power GPS, 5 monitor operation) and a 24V regulator. A precision clock ensures reliable GPS pulse reception.

2.3 Trip Component Modules

Classified as trip/logic relays, trip modules integrate multi-relay functions (closing holding/manual trip/trip current/protection) in 0.5A/1A specs. Valve parameter adjustments don’t require relay replacement. CPU-driven logic relays connect to closing intermediates, with closed negative power supplies preventing switch-induced transformer damage and reducing maintenance costs.

4. Application of Data Acquisition Component

The data acquisition component is composed of a 14 - bit precision AVD converter with fairly high reliability and a filter circuit with multi - way switches. Among them, the 14 - bit precision AVD converter is a new type constructed by a synchronous circuit. Therefore, using the data acquisition component to protect the transformer has the characteristics of high accuracy, strong stability, low power consumption, and fast conversion speed.

Meanwhile, in the system measurement of the data acquisition component, there is no need to rely on external auxiliary tools. Various errors in power operation can be adjusted through a built - in chip with high measurement precision. In addition, the data acquisition component has unique input and output functions. The CPU system of the data acquisition component has 16 preset switches, 10 external output switches, and one 24V regulated power supply switch. Through these 10 external output switches, the exclusive purpose of supplying power to the GPS in the system can be achieved. The other 5 switches are mainly responsible for the supervision and control of the operation status of the data acquisition component.

Finally, an exquisite clock circuit is set in the data acquisition component, which makes the clock chip more accurate and delicate, thus ensuring that the protection device of the transformer can fully receive the GPS pulse signal.

5. Maintenance Measures for Distribution Transformers

5.1 Strengthen O&M Management

Most distribution transformer failures result from inadequate maintenance and weak management. Thus, enhance equipment O&M: promptly address defects/hazards, follow procedures strictly, and improve failure prevention. Regular inspections/maintenance are vital to ensure safe operation and identify issues timely.

5.2 Optimize Protection Configuration

Install lightning arresters to prevent overvoltage - induced internal short circuits, and test insulation resistance regularly to avoid burnout. O&M personnel must carefully select fuse elements and low - voltage overcurrent settings.

5.3 Standardize Relay Protection O&M

Regular inspections/maintenance ensure reliable relay protection operation, which is critical for power system stability. Steps include: understanding equipment initial states, analyzing operational data, and adopting new technologies to maintain scientific O&M.

Secondary cables in strong EM fields make non - electrical protection sensitive to interference, risking false trips. Countermeasures:

5.4 Enhance Secondary Cable Protection

• Protect external connections (e.g., gas relays), seal cable entrances, and add rain shields.

• Use shielded cables; separate AC/DC laying.

• Anti - interference measures: delay settings, 55% - 70% UN operating voltage, and voltage adjustment under symmetric DC insulation.

• Route cables away from high - voltage/control lines; ground shielded cables at both ends.