Method for measuring liquid level of liquid in container

Abstract

The invention relates to the field of intelligent measurement and provides a method for measuring the liquid level of liquid in a container. The method includes the following steps that A, two points are selected from the side wall of the container and are the upper measuring point and the lower measuring point respectively, the upper measuring point is higher than the lower measuring point, and pressure intensity sensors are installed to measure the pressure intensity value of the upper measuring point and the pressure intensity value of the lower measuring point respectively ; B, the height between the liquid level and the upper measuring point is calculated through the pressure intensity value of the upper measuring point, the pressure intensity value of the lower measuring point and the vertical distance between the upper measuring point and the lower measuring point, and the calculation formula is shown as h1=P1h2/(P2-P1), wherein P1 is the pressure intensity value of the upper measuring point, P2 is the pressure intensity value of the lower measuring point, h1 is the height between the upper measuring point and the liquid level, and h2 is the vertical distance between the upper measuring point and the lower measuring point. According to the method, the accurate liquid level height can be obtained through calculation by measuring the pressure intensity values of two different heights of liquid in the container, measuring precision is high, errors are small, and measuring errors caused by factors such as temperature and density are effectively avoided.

Description

technical field [0001] The invention relates to the field of intelligent measurement, in particular to a method for measuring liquid level in a container. Background technique [0002] At present, there are basically three types of oil conservator oil level gauges for converter transformers and smoothing reactors in operation in converter stations: (1) float lever oil level gauge; (2) glass tube oil level gauge; (3) float Hydraulic oil level gauge. Since the oil temperature of the converter and smoothing reactor varies greatly during operation (about 20°C-100°C), the oil level of the oil conservator also changes relatively greatly, so the oil level of the oil conservator and the oil filling amount of the converter, There is a close relationship between the oil temperature and the expansion coefficient of the oil. If the judgment is inaccurate, it is easy to cause a forced stop accident of the transformer. The previous two oil level gauges are installed at the bottom of the...

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Problems solved by technology

Since the oil temperature of the converter and smoothing reactor varies greatly during operation (about 20°C-100°C), the oil level of the oil conservator also changes relatively greatly, so the oil level of the oil conservator and the oil filling amount of the converter, There is a close relationship between the oil temperature and the expansion coefficient of the oil. If the judgment is inaccurate, it is easy to cause a forced stop accident of the transformer

The previous two oil level gauges are installed at the bottom of the converter oil conservator. Since the oil conservator is too high and blocked by the tank, the oil level cannot be visually checked during on-site inspections, and the correspondence between the oil temperature change and the actual oil level of the conservator cannot be judged. Oil level, when the oil level of the oil conservator suddenly reaches an ultra-low oil level, the contact alarm signal can be issued

The third type of oil level gauge can monitor the oil level in the transformer inspection walkway, but due to the temperature compensation of the pressure transmission capillary and the oil level change caused by the transformer oil temperature change, it cannot directly judge whether the oil level is correct

However, the above three types of oil level gauges have common shortcomings: (1) Inspection and calibration need to be carried out when the transformer is out of service, and the workload of regular calibration and inspection is heavy (generally, calibration and maintenance are not performed after installation and operation)

(2) The oil level of the oil conservator and the temperature change of the transformer cannot be clearly displayed and pre-alarmed

The height h will change with the density ρ, so using a single pressure sensor to measure and calculate the height h has low accuracy

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